/* ================================================================
   硬件系统热设计计算平台 — 专业工程主题 v2.0
   主色调：深海军蓝 + 热力橙红 + 精密冷钢
   灵感：工业仪表盘 × 现代 SaaS Dashboard
   ================================================================ */

:root {
    /* ── 主色系 ── */
    --primary:        #E8441A;    /* 热力橙红 — CTA、重点元素 */
    --primary-dark:   #C13312;
    --primary-light:  #FF6B3D;
    --accent:         #FF9F43;    /* 暖橙 — 高亮、图标 */

    /* ── 中性色系（中深色背景体系，v2.1 调亮） ── */
    --bg:             #1A1F2E;    /* 页面底色：深蓝灰，不再纯黑 */
    --bg-card:        #222840;    /* 卡片背景：可见蓝调 */
    --bg-elevated:    #2A3250;    /* 面板/抬起层：更亮的蓝灰 */
    --bg-hover:       #323B5A;    /* hover：明显高亮 */
    --border:         #3A4466;    /* 边框：可见蓝色调 */
    --border-light:   #4A5578;    /* 浅边框 */

    /* ── 文字色系 ── */
    --text:           #ECF0FF;    /* 主文字：冷白 */
    --text-secondary: #9BA8C0;    /* 次要文字：比之前更亮 */
    --text-muted:     #6070A0;    /* 失效/占位 */

    /* ── 语义色 ── */
    --success:        #26D07C;
    --success-bg:     rgba(38, 208, 124, 0.1);
    --warning:        #FF9F43;
    --warning-bg:     rgba(255, 159, 67, 0.07);  /* 深色主题：稍降透明度避免泛黄 */
    --danger:         #FF4D4F;
    --danger-bg:      rgba(255, 77, 79, 0.1);
    --info:           #3B82F6;
    --info-bg:        rgba(59, 130, 246, 0.1);

    /* ── 阴影 ── */
    --shadow-sm:  0 1px 4px rgba(0,0,0,0.4);
    --shadow:     0 4px 16px rgba(0,0,0,0.5);
    --shadow-lg:  0 8px 32px rgba(0,0,0,0.6);
    --shadow-glow: 0 0 24px rgba(232, 68, 26, 0.25);

    /* ── 圆角 ── */
    --radius-sm: 6px;
    --radius:    10px;
    --radius-lg: 16px;

    /* ── 过渡 ── */
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ================================================================
   Reset & Base
   ================================================================ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', 'Segoe UI', 'Microsoft YaHei', -apple-system, sans-serif;
    font-size: 15px;
    line-height: 1.65;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--primary-light);
    text-decoration: none;
    transition: var(--transition);
}
a:hover { color: var(--accent); }

.container {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ================================================================
   Scrollbar
   ================================================================ */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-card); }
::-webkit-scrollbar-thumb { background: var(--border-light); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary); }

/* ================================================================
   导航栏
   ================================================================ */
.navbar {
    background: rgba(15, 17, 23, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 24px;
    height: 60px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text);
    letter-spacing: -0.01em;
}

.nav-brand i {
    font-size: 1.4rem;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0.25rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    border-bottom: none;
    transition: var(--transition);
}
.nav-link:hover {
    color: var(--text);
    background: var(--bg-elevated);
}
.nav-link.active {
    color: var(--primary-light);
    background: rgba(232, 68, 26, 0.12);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}
.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text);
    border-radius: 1px;
    transition: var(--transition);
}

/* ================================================================
   Hero
   ================================================================ */
.hero {
    background:
        radial-gradient(ellipse at 20% 50%, rgba(232, 68, 26, 0.18) 0%, transparent 60%),
        radial-gradient(ellipse at 80% 20%, rgba(255, 159, 67, 0.12) 0%, transparent 50%),
        linear-gradient(160deg, #1A1F2E 0%, #1E2440 60%, #1A1F2E 100%);
    color: var(--text);
    padding: 80px 0 60px;
    border-bottom: 1px solid var(--border);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(circle at 1px 1px, rgba(255,255,255,0.04) 1px, transparent 0);
    background-size: 40px 40px;
    pointer-events: none;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
}

.hero h1 {
    font-size: 2.6rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, #FFFFFF 0%, #C8D4E8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.7;
}

.hero-features {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 2rem;
}

.hero-feature {
    display: flex;
    align-items: center;
    gap: 12px;
    background: rgba(255,255,255,0.04);
    border: 1px solid var(--border);
    padding: 12px 16px;
    border-radius: var(--radius);
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: var(--transition);
}
.hero-feature:hover {
    border-color: var(--primary);
    background: rgba(232, 68, 26, 0.06);
    color: var(--text);
}
.hero-feature i {
    color: var(--primary-light);
    width: 18px;
    text-align: center;
}

.hero-cta {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* ================================================================
   Buttons
   ================================================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 22px;
    border: none;
    border-radius: var(--radius);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    text-decoration: none;
    letter-spacing: 0.01em;
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: #fff;
    box-shadow: 0 2px 12px rgba(232, 68, 26, 0.4);
}
.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(232, 68, 26, 0.55);
    color: #fff;
}
.btn-primary:active { transform: translateY(0); }

.btn-secondary {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-light);
}
.btn-secondary:hover {
    background: var(--bg-elevated);
    border-color: var(--primary);
    color: var(--text);
}

.btn-large {
    padding: 13px 32px;
    font-size: 1rem;
}
.btn-small {
    padding: 6px 14px;
    font-size: 0.82rem;
}
.btn-block {
    width: 100%;
}

/* ================================================================
   Hero SVG Diagram
   ================================================================ */
.thermal-diagram {
    width: 100%;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 16px;
}
.diagram-label {
    font-size: 13px;
    fill: var(--text-secondary);
    font-family: 'Inter', sans-serif;
}

/* ================================================================
   Section Layout
   ================================================================ */
section {
    padding: 64px 0;
}

.section-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text);
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 40px;
    font-size: 0.95rem;
}

/* ================================================================
   快速工具
   ================================================================ */
.quick-tools {
    padding: 56px 0;
    background:
        linear-gradient(180deg, var(--bg-card) 0%, var(--bg) 100%);
    border-bottom: 1px solid var(--border);
}

.quick-tools h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 8px;
    text-align: center;
    letter-spacing: -0.02em;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.tool-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    transition: var(--transition);
}
.tool-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}
.tool-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 4px;
}
.tool-card p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 16px;
}

.tool-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, rgba(232,68,26,0.2), rgba(255,159,67,0.1));
    border: 1px solid rgba(232,68,26,0.3);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
}
.tool-icon i {
    font-size: 1.4rem;
    background: linear-gradient(135deg, var(--primary-light), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.quick-calc {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 12px;
}

.quick-input {
    padding: 9px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    color: var(--text);
    transition: var(--transition);
    width: 100%;
}
.quick-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(232, 68, 26, 0.12);
}
.quick-input::placeholder { color: var(--text-muted); }

.quick-result {
    padding: 10px 14px;
    background: var(--success-bg);
    border: 1px solid rgba(38, 208, 124, 0.25);
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--success);
    min-height: 40px;
}

/* ================================================================
   Calculator Panels
   ================================================================ */
.calculator-layout,
.design-layout,
.airflow-layout,
.duct-layout,
.selection-layout {
    display: grid;
    grid-template-columns: 1fr 1.6fr;
    gap: 28px;
    align-items: start;
}

.calc-panel,
.design-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    position: sticky;
    top: 80px;
}

.calc-panel h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 8px;
}
.calc-panel h3::before {
    content: '';
    display: block;
    width: 3px;
    height: 18px;
    background: linear-gradient(to bottom, var(--primary), var(--accent));
    border-radius: 2px;
}

.param-group {
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}
.param-group:last-of-type { border-bottom: none; }

.param-group h4 {
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.param-group h4 i { color: var(--primary-light); font-size: 0.9rem; }

/* ── 输入框 ── */
.input-group {
    margin-bottom: 14px;
}
.input-group label {
    display: block;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
    letter-spacing: 0.01em;
}
.input-group input:not([type="range"]),
.input-group select {
    width: 100%;
    padding: 9px 12px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    color: var(--text);
    transition: var(--transition);
    appearance: none;
    -webkit-appearance: none;
}
.input-group select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238892A4' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 32px;
}
.input-group input:not([type="range"]):focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary);
    background: var(--bg-hover);
    box-shadow: 0 0 0 3px rgba(232, 68, 26, 0.12);
}
.input-group input:not([type="range"])::placeholder { color: var(--text-muted); }

/* slider 在 input-group 内：让 range-slider-wrapper 撑满宽度 */
.input-group .range-slider-wrapper {
    width: 100%;
}

.input-hint {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 4px;
    font-style: italic;
}

.input-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 12px;
}

.calculated-param {
    background: rgba(255, 159, 67, 0.08);
    border: 1px solid rgba(255, 159, 67, 0.25);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.88rem;
    color: var(--accent);
    font-weight: 600;
}

/* ================================================================
   Result Cards
   ================================================================ */
.result-summary {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-bottom: 24px;
}

.result-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}
.result-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
}
.result-card.highlight {
    border-color: rgba(232, 68, 26, 0.4);
    background: rgba(232, 68, 26, 0.06);
}

.result-label {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.result-value {
    font-size: 2.4rem;
    font-weight: 800;
    color: var(--text);
    line-height: 1;
    letter-spacing: -0.03em;
    font-variant-numeric: tabular-nums;
}
.result-card.highlight .result-value {
    background: linear-gradient(135deg, var(--primary-light), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.result-unit {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

.result-status {
    margin-top: 10px;
    font-size: 0.82rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 20px;
    display: inline-block;
}
.status-good {
    color: var(--success);
    background: var(--success-bg);
}
.status-warning {
    color: var(--warning);
    background: var(--warning-bg);
}
.status-danger {
    color: var(--danger);
    background: var(--danger-bg);
}

/* ================================================================
   Result Panel / Design Panel
   ================================================================ */
.result-panel,
.design-result {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
}
.result-panel h3,
.design-result h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 8px;
}
.result-panel h3 i,
.design-result h3 i { color: var(--primary-light); }

/* ================================================================
   Tables
   ================================================================ */
.result-table,
.fan-table,
.device-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.88rem;
}

.result-table th,
.fan-table th {
    background: var(--bg-elevated);
    color: var(--text-secondary);
    padding: 10px 14px;
    text-align: left;
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    border-bottom: 1px solid var(--border);
}

.result-table td,
.fan-table td {
    padding: 11px 14px;
    border-bottom: 1px solid var(--border);
    color: var(--text);
}

.result-table tbody tr:hover,
.fan-table tbody tr:hover {
    background: var(--bg-elevated);
}
.result-table tbody tr:last-child td,
.fan-table tbody tr:last-child td {
    border-bottom: none;
}

/* ── 设备参考表 ── */
.device-table th {
    background: var(--bg-elevated);
    color: var(--text-secondary);
    padding: 10px 14px;
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    border-bottom: 1px solid var(--border);
}
.device-table td {
    padding: 10px 14px;
    border-bottom: 1px solid var(--border);
    color: var(--text);
}
.device-table tbody tr:last-child td { border-bottom: none; }

/* ================================================================
   材料库
   ================================================================ */
.material-database,
.heatsink-library {
    margin-top: 28px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
}
.material-database h3,
.heatsink-library h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 8px;
}

.material-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
}

.material-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px;
    border-left: 3px solid var(--primary);
    transition: var(--transition);
}
.material-card:hover {
    border-left-color: var(--accent);
    background: var(--bg-hover);
}
.material-card h4 {
    font-size: 0.88rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 10px;
}
.material-card ul {
    list-style: none;
    padding: 0;
}
.material-card li {
    font-size: 0.82rem;
    color: var(--text-secondary);
    padding: 3px 0;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
}
.material-card li:last-child { border-bottom: none; }

/* ================================================================
   散热器可视化
   ================================================================ */
.heatsink-viz {
    margin-bottom: 20px;
}
#heatsinkCanvas {
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

/* ── 滑块布局 ── */
.slider-input-group {
    margin-bottom: 16px;
}

/* label 和数值同行 */
.slider-label-row {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 6px;
}
.slider-label-row label {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    letter-spacing: 0.01em;
    margin-bottom: 0;      /* 覆盖 .input-group label 的 margin-bottom */
}

.slider-value {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
    min-width: 36px;
    text-align: right;
}

/* ── Slider: 彻底用 webkit-slider-runnable-track 分段渲染 ── */
/* 通过 JS 设置 input 的 --pct CSS variable，CSS 自动计算分段色 */
.range-slider-wrapper {
    display: block;
    width: 100%;
    margin: 10px 0 8px;
}

/* fill div 不渲染，仅保留 DOM 供 JS 兼容调用 */
.range-slider-fill {
    display: none;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    border-radius: 3px;
    /* 分段渐变：JS 动态更新 --slider-pct，默认 50% */
    background: linear-gradient(
        to right,
        #E8441A 0%,
        #FF9F43 var(--slider-pct, 50%),
        #566080 var(--slider-pct, 50%),
        #566080 100%
    );
    outline: none;
    cursor: pointer;
    display: block;
    margin: 4px 0;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary);
    cursor: pointer;
    box-shadow: 0 0 8px rgba(232, 68, 26, 0.5);
    border: 2px solid var(--bg-card);
    transition: all 0.15s;
    /* margin-top 已移除：父容器 flex align-items:center 自动居中 */
}
input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 12px rgba(232, 68, 26, 0.7);
}
input[type="range"]::-webkit-slider-runnable-track {
    height: 4px;
    background: transparent !important;
    border-radius: 2px;
}

input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border: 2px solid var(--bg-card);
    border-radius: 50%;
    background: var(--primary);
    cursor: pointer;
    box-shadow: 0 0 8px rgba(232, 68, 26, 0.5);
}
input[type="range"]::-moz-range-track {
    height: 4px;
    background: var(--border);
    border-radius: 2px;
}
input[type="range"]::-moz-range-progress {
    height: 4px;
    background: linear-gradient(to right, var(--primary), var(--accent));
    border-radius: 2px;
}

/* ================================================================
   公式框
   ================================================================ */
.formula-box {
    background: var(--info-bg);
    border: 1px solid rgba(59, 130, 246, 0.25);
    padding: 18px;
    border-radius: var(--radius);
    margin: 14px 0;
}
.formula-box code {
    display: block;
    font-family: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
    font-size: 0.95rem;
    background: var(--bg-elevated);
    color: var(--accent);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    margin: 8px 0;
    border: 1px solid var(--border);
    letter-spacing: 0.02em;
}
.formula-note {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 8px;
}

/* ================================================================
   设计建议块
   ================================================================ */
.design-tips,
.recommendations {
    margin-top: 20px;
}
.design-tips h4,
.recommendations h4 {
    font-size: 0.82rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-secondary);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.design-tips ul,
.recommendations ul {
    list-style: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.design-tips li,
.recommendations li {
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 8px 12px;
    background: var(--bg-elevated);
    border-radius: var(--radius-sm);
    border-left: 2px solid var(--success);
    display: flex;
    align-items: flex-start;
    gap: 8px;
    line-height: 1.5;
}

/* ================================================================
   风扇选型 — Filter Panel
   ================================================================ */
.filter-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    height: fit-content;
    position: sticky;
    top: 80px;
}
.filter-panel h3 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-group {
    margin-bottom: 18px;
}
.filter-group > label:first-child,
.filter-group > h4 {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-secondary);
    margin-bottom: 10px;
    display: block;
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 7px;
}
.checkbox-group label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.88rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    padding: 4px 6px;
    border-radius: var(--radius-sm);
}
.checkbox-group label:hover {
    color: var(--text);
    background: var(--bg-elevated);
}

input[type="checkbox"] {
    width: 15px;
    height: 15px;
    accent-color: var(--primary);
    cursor: pointer;
}

/* ── Fan List Panel ── */
.fan-list-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    display: flex;
    flex-direction: column;
    max-height: calc(100vh - 140px);
    min-height: 600px;
}

.list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}
.list-header h3 {
    margin: 0;
    font-size: 1rem;
    font-weight: 700;
    color: var(--text);
}
.list-header .count {
    color: var(--primary-light);
    font-weight: 700;
    font-size: 0.85rem;
}

.sort-controls {
    display: flex;
    align-items: center;
    gap: 8px;
}
.sort-controls label {
    font-size: 0.82rem;
    color: var(--text-muted);
}

.fan-table-container {
    overflow: auto;
    flex: 1;
    scrollbar-width: thin;
    scrollbar-color: var(--border-light) var(--bg-card);
}

.fan-table thead {
    position: sticky;
    top: 0;
    z-index: 10;
}
.fan-table thead th {
    background: var(--bg-elevated);
    font-size: 0.75rem;
}

.fan-row { transition: background 0.15s; }
.fan-row:hover { background: var(--bg-elevated); }

.btn-icon {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 1rem;
    cursor: pointer;
    padding: 5px 6px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}
.btn-icon:hover {
    color: var(--primary-light);
    background: rgba(232,68,26,0.1);
}

.fan-select {
    width: 15px;
    height: 15px;
    accent-color: var(--primary);
    cursor: pointer;
}

/* ── Fan Comparison ── */
.comparison-panel {
    margin-top: 16px;
    padding: 16px 20px;
    background: rgba(232, 68, 26, 0.06);
    border: 1px solid rgba(232, 68, 26, 0.25);
    border-radius: var(--radius);
    flex-shrink: 0;
}
.comparison-panel h4 {
    margin: 0 0 12px;
    font-size: 0.88rem;
    font-weight: 700;
    color: var(--primary-light);
    display: flex;
    align-items: center;
    gap: 8px;
}

/* ================================================================
   风扇匹配 & PWM
   ================================================================ */
.matching-panel,
.pwm-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-top: 24px;
}
.matching-panel h3,
.pwm-panel h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 8px;
}
.matching-panel h3 i,
.pwm-panel h3 i { color: var(--primary-light); }

/* ================================================================
   风量指示器
   ================================================================ */
.airflow-indicator {
    display: flex;
    gap: 4px;
    align-items: center;
    margin-top: 12px;
}
.indicator-bar {
    flex: 1;
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
}
.indicator-fill {
    height: 100%;
    border-radius: 4px;
    transition: width 0.4s ease;
    background: linear-gradient(90deg, var(--success), var(--accent), var(--danger));
}

/* ================================================================
   风道设计 — 气流方案
   ================================================================ */
.airflow-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin: 14px 0;
}
.airflow-option {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    padding: 14px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
}
.airflow-option:has(input[type="radio"]:checked) {
    border-color: var(--primary);
    background: rgba(232, 68, 26, 0.06);
}
.airflow-option:hover {
    border-color: var(--border-light);
    background: var(--bg-hover);
}
.airflow-option input[type="radio"] {
    accent-color: var(--primary);
    margin-top: 2px;
    flex-shrink: 0;
}

/* ================================================================
   CFD 案例库卡片
   ================================================================ */
.cfd-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 20px;
}
.cfd-case-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
}
.cfd-case-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

/* ================================================================
   案例库
   ================================================================ */
.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(520px, 1fr));
    gap: 24px;
}

.case-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
}
.case-card:hover {
    border-color: var(--border-light);
    box-shadow: var(--shadow);
    transform: translateY(-2px);
}

.case-header {
    padding: 20px 24px 16px;
    border-bottom: 1px solid var(--border);
}

.case-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 3px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    margin-bottom: 10px;
}
.case-tag.server   { background: rgba(59,130,246,0.1); color: var(--info); border: 1px solid rgba(59,130,246,0.25); }
.case-tag.automotive { background: var(--warning-bg); color: var(--warning); border: 1px solid rgba(255,159,67,0.25); }
.case-tag.telecom  { background: rgba(168,85,247,0.1); color: #c084fc; border: 1px solid rgba(168,85,247,0.25); }
.case-tag.industrial { background: var(--success-bg); color: var(--success); border: 1px solid rgba(38,208,124,0.25); }
.case-tag.robot    { background: rgba(232,68,26,0.1); color: var(--primary-light); border: 1px solid rgba(232,68,26,0.25); }

.case-header h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text);
}

.case-image {
    background: var(--bg);
    overflow: hidden;
}
.case-image svg, .case-image img {
    width: 100%;
    display: block;
    background: var(--bg);
}

.case-content {
    padding: 20px 24px;
}

.case-specs {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-bottom: 16px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
}
.spec-item {
    display: flex;
    align-items: center;
    gap: 7px;
    font-size: 0.83rem;
    color: var(--text-secondary);
}
.spec-item i { color: var(--primary-light); }

.challenge-list, .solution-list {
    list-style: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin: 10px 0;
}
.challenge-list li {
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 5px 0 5px 12px;
    border-left: 2px solid var(--border);
}
.solution-list li {
    font-size: 0.85rem;
    color: var(--success);
    padding: 5px 0;
}

.case-results-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 12px;
    font-size: 0.85rem;
}
.case-results-table td {
    padding: 7px 12px;
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
}
.case-results-table td:first-child { color: var(--text); font-weight: 600; }
.case-results-table td:last-child {
    color: var(--success);
    font-weight: 600;
    text-align: right;
}
.case-results-table tr:last-child td { border-bottom: none; }

.case-highlight {
    margin-top: 18px;
    padding: 16px 18px;
    background: rgba(232, 68, 26, 0.05);
    border: 1px solid rgba(232, 68, 26, 0.2);
    border-radius: var(--radius);
}
.case-highlight h4 {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--primary-light);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.case-highlight p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 8px;
}
.case-highlight p:last-child { margin-bottom: 0; }
.case-highlight strong { color: var(--text); font-weight: 600; }

/* ================================================================
   案例筛选 Tab
   ================================================================ */
.case-filters {
    display: flex;
    gap: 8px;
    margin-bottom: 28px;
    flex-wrap: wrap;
}
.filter-btn {
    padding: 6px 18px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}
.filter-btn:hover {
    border-color: var(--border-light);
    color: var(--text);
}
.filter-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: #fff;
}

/* ================================================================
   Footer
   ================================================================ */
.footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 56px 0 32px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer h4 {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 14px;
}
.footer p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.footer-links a {
    font-size: 0.88rem;
    color: var(--text-secondary);
    transition: var(--transition);
}
.footer-links a:hover { color: var(--primary-light); }
.footer-links i {
    width: 16px;
    text-align: center;
    margin-right: 6px;
    color: var(--text-muted);
}

.footer-bottom {
    padding-top: 24px;
    border-top: 1px solid var(--border);
    text-align: center;
    font-size: 0.82rem;
    color: var(--text-muted);
}

/* ================================================================
   导出按钮区域
   ================================================================ */
.export-actions {
    display: flex;
    gap: 10px;
    margin-top: 20px;
    flex-wrap: wrap;
}

/* ================================================================
   Section Headers with accent stripe
   ================================================================ */
.section-header {
    margin-bottom: 36px;
}
.section-header h2 {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--text);
    letter-spacing: -0.03em;
    display: flex;
    align-items: center;
    gap: 12px;
}
.section-header h2 i { color: var(--primary-light); }
.section-header p {
    color: var(--text-secondary);
    font-size: 0.92rem;
    margin-top: 6px;
}

/* 章节分割背景 */
section:nth-child(even) {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

/* ================================================================
   通用工具
   ================================================================ */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 2px 8px;
    border-radius: 20px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.badge-success { background: var(--success-bg); color: var(--success); }
.badge-warning { background: var(--warning-bg); color: var(--warning); }
.badge-danger  { background: var(--danger-bg);  color: var(--danger); }
.badge-info    { background: var(--info-bg);    color: var(--info); }

.divider {
    border: none;
    border-top: 1px solid var(--border);
    margin: 24px 0;
}

.text-success { color: var(--success); }
.text-warning { color: var(--warning); }
.text-danger  { color: var(--danger); }
.text-muted   { color: var(--text-muted); }

/* ================================================================
   PWM 加载按钮
   ================================================================ */
.load-pwm-btn {
    cursor: pointer;
    position: relative;
    overflow: hidden;
}
.load-pwm-btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at center, rgba(255,255,255,0.15) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.3s;
}
.load-pwm-btn:hover::after { opacity: 1; }
.load-pwm-btn i { margin-right: 6px; }

/* ================================================================
   Responsive
   ================================================================ */
@media (max-width: 1200px) {
    .cases-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 1024px) {
    .calculator-layout,
    .design-layout,
    .airflow-layout,
    .duct-layout,
    .selection-layout {
        grid-template-columns: 1fr;
    }
    .calc-panel { position: static; }
    .filter-panel { position: static; }

    .hero .container {
        grid-template-columns: 1fr;
    }
    .hero-diagram { display: none; }
    .hero { padding: 60px 0 40px; }
    .hero h1 { font-size: 2rem; }
}

@media (max-width: 768px) {
    .nav-toggle { display: flex; }
    .nav-menu {
        display: none;
        position: absolute;
        top: 60px; left: 0; right: 0;
        background: var(--bg-card);
        border-bottom: 1px solid var(--border);
        flex-direction: column;
        gap: 0;
        padding: 8px 0;
    }
    .nav-menu.open { display: flex; }
    .nav-link {
        padding: 12px 24px;
        border-radius: 0;
    }

    .result-summary { grid-template-columns: 1fr; }
    .cases-grid { grid-template-columns: 1fr; }
    .material-grid { grid-template-columns: 1fr; }
    .tools-grid { grid-template-columns: 1fr; }

    .hero h1 { font-size: 1.75rem; }
    section { padding: 40px 0; }
    .container { padding: 0 16px; }
}

/* ================================================================
   温度梯度条 & 安全裕量仪表
   ================================================================ */
.temp-gradient-bar {
    margin: 16px 0 12px;
    padding: 14px 16px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}
.tgb-title {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.tgb-track {
    display: flex;
    height: 28px;
    border-radius: 6px;
    overflow: hidden;
    gap: 1px;
}
.tgb-seg {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 700;
    color: rgba(255,255,255,0.9);
    transition: width 0.4s ease;
    min-width: 0;
    overflow: hidden;
}
.tgb-jc { background: linear-gradient(135deg, #E8441A, #C13312); }
.tgb-cs { background: linear-gradient(135deg, #FF9F43, #E07B1A); }
.tgb-sa { background: linear-gradient(135deg, #3B82F6, #1E60D0); }
.tgb-labels {
    display: flex;
    justify-content: space-between;
    margin-top: 6px;
    font-size: 0.78rem;
    font-variant-numeric: tabular-nums;
}

.margin-gauge {
    margin: 0 0 16px;
    padding: 14px 16px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}
.mg-title {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.mg-bar-wrap {
    position: relative;
    height: 20px;
    background: var(--bg-hover);
    border-radius: 10px;
    overflow: hidden;
}
.mg-bar {
    height: 100%;
    border-radius: 10px;
    transition: width 0.4s ease, background 0.3s;
}
.mg-bar-label {
    position: absolute;
    right: 8px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.75rem;
    font-weight: 700;
}
.mg-detail {
    margin-top: 6px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* ================================================================
   材料导热系数对比表
   ================================================================ */
.material-compare-table {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    font-size: 0.85rem;
}
.mct-header {
    display: grid;
    grid-template-columns: 1.8fr 1.2fr 1.8fr 1.8fr;
    gap: 8px;
    padding: 10px 14px;
    background: var(--bg-hover);
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.mct-group-label {
    padding: 6px 14px 4px;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--accent);
    background: rgba(255,159,67,0.05);
    border-top: 1px solid var(--border);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.mct-row {
    display: grid;
    grid-template-columns: 1.8fr 1.2fr 1.8fr 1.8fr;
    gap: 8px;
    padding: 7px 14px;
    border-top: 1px solid rgba(42,51,72,0.5);
    align-items: center;
    transition: background 0.15s;
}
.mct-row:hover { background: var(--bg-hover); }
.mct-name { color: var(--text); }
.mct-val  { color: var(--accent); font-weight: 600; font-variant-numeric: tabular-nums; font-size: 0.8rem; }
.mct-use  { color: var(--text-secondary); font-size: 0.78rem; }
.mct-bar  {
    height: 10px;
    background: var(--bg-hover);
    border-radius: 5px;
    overflow: hidden;
}
.mct-fill {
    height: 100%;
    width: 50%;
    border-radius: 5px;
    background: var(--primary);
    transition: width 0.3s ease;
}
.mct-note {
    grid-column: 1 / -1;
    display: block !important;
    padding: 8px 14px;
    color: var(--text-muted);
    font-size: 0.75rem;
    font-style: italic;
    border-top: 1px solid var(--border);
}

/* 反算按钮（outline 样式）*/
.btn-outline {
    background: transparent;
    border: 1px solid var(--primary);
    color: var(--primary-light);
}
.btn-outline:hover {
    background: rgba(232,68,26,0.1);
}


/* ── Toast 通知 ── */
#toast-container {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 99999;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    pointer-events: none;
}
.toast {
    background: #1e293b;
    color: #f1f5f9;
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    box-shadow: 0 4px 16px rgba(0,0,0,0.35);
    border-left: 4px solid #3b82f6;
    opacity: 0;
    transform: translateY(12px);
    transition: opacity 0.25s, transform 0.25s;
    pointer-events: none;
    white-space: nowrap;
}
.toast.show { opacity: 1; transform: translateY(0); }
.toast.success { border-left-color: #10b981; }
.toast.warning { border-left-color: #f59e0b; }
.toast.error   { border-left-color: #ef4444; }


/* 手机竖屏 480px */
@media (max-width: 480px) {
    .container { padding: 0 12px; }
    h1, .hero h1 { font-size: 1.4rem; }
    .result-summary { grid-template-columns: 1fr !important; }
    input[type="number"] { font-size: 16px; }
    .nav-link { font-size: 0.8rem; padding: 10px 12px; }
}