/* ============================================
   飞轮储能UPS系统 — Machined Precision 设计系统
   天印制造
   ============================================ */

/* ----- Google Fonts: Space Grotesk (display, Latin only, ~20KB) ----- */
@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&display=swap');

/* ============================================
   Design Tokens
   ============================================ */
:root {
    --steel-dark:    #232427;
    --steel-surface: #2E3035;
    --steel-elevated: #34363C;
    --aluminum:      #E0D9CC;
    --patina:        #9B8E7E;
    --copper:        #D4874A;
    --copper-deep:   #B8703A;
    --rule:          #3A3D42;
    --rule-subtle:   #2C2E32;
    --bg-deep:       #1B1D20;
}

/* ============================================
   Base
   ============================================ */
html { scroll-behavior: smooth; }
body {
    overflow-x: hidden;
    background: var(--steel-dark);
    color: var(--aluminum);
}

/* Dot-grid texture */
body::before {
    content: '';
    position: fixed; inset: 0;
    pointer-events: none; z-index: 0;
    background-image: radial-gradient(circle, rgba(255,255,255,0.025) 1px, transparent 1px);
    background-size: 24px 24px;
}

/* Scrollbar */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: var(--steel-dark); }
::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 2px; }
::-webkit-scrollbar-thumb:hover { background: var(--patina); }

/* ============================================
   Accessibility
   ============================================ */

/* Visible focus ring for keyboard navigation */
:focus-visible {
    outline: 2px solid var(--copper);
    outline-offset: 2px;
    border-radius: 2px;
}

/* Respect user motion preferences */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    html { scroll-behavior: auto; }
    .flywheel-sim canvas { animation: none !important; }
    .reveal { opacity: 1; transform: none; transition: none; }
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, .counter, .rpm-val, .energy-val,
.perf-summary-card .text-3xl, .spec-item span:last-child {
    font-family: 'Space Grotesk', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}
.font-mono, code, .spec-item span:last-child {
    font-family: 'Space Grotesk', 'JetBrains Mono', 'Consolas', monospace;
}
.section-heading h2 {
    font-family: 'Space Grotesk', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    font-weight: 600;
    letter-spacing: -0.02em;
}

/* ============================================
   Navigation
   ============================================ */
#navbar {
    background: rgba(35, 36, 39, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--rule-subtle);
}
.nav-link {
    font-family: 'Space Grotesk', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    font-size: 0.78rem;
    letter-spacing: 0.02em;
    transition: color 0.2s ease, background 0.2s ease;
}
.nav-link.active {
    color: var(--copper) !important;
    background: rgba(212, 135, 74, 0.08);
}
#navbar .w-8.h-8.rounded-full {
    background: linear-gradient(135deg, var(--copper), var(--copper-deep)) !important;
}

/* ============================================
   Animations (restrained)
   ============================================ */
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}
.animate-fadeIn  { animation: fadeIn 0.7s ease-out forwards; }
.animate-slideUp { animation: slideUp 0.7s ease-out forwards; opacity: 0; }

.reveal {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity 0.45s ease-out, transform 0.45s ease-out;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ============================================
   Cards — Unified
   ============================================ */
.metric-card, .info-card, .arch-card, .workflow-card, .spec-card,
.comm-feature, .code-feature-card, .chart-container,
.perf-summary-card, .safety-card, .info-section-card,
.team-card, .pioneer-card {
    background: linear-gradient(180deg, var(--steel-surface), var(--steel-dark));
    border: 1px solid var(--rule);
    border-radius: 6px;
    transition: all 0.25s ease;
}
.metric-card:hover, .info-card:hover, .arch-card:hover, .workflow-card:hover,
.spec-card:hover, .comm-feature:hover, .code-feature-card:hover,
.chart-container:hover, .perf-summary-card:hover, .safety-card:hover,
.info-section-card:hover, .team-card:hover, .pioneer-card:hover {
    border-color: var(--rule);
    box-shadow: 0 8px 24px rgba(0,0,0,0.4);
    transform: translateY(-2px);
}

.info-card        { padding: 2rem; }
.arch-card        { padding: 1.5rem; border-left: 3px solid var(--rule); }
.workflow-card    { padding: 1.5rem; width: 220px; text-align: center; }
.workflow-icon    { width: 56px; height: 56px; border-radius: 50%; display: flex; align-items: center; justify-content: center; margin: 0 auto; background: var(--steel-dark); }
.spec-card        { padding: 1.5rem; }
.spec-card-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; padding-bottom: 0.75rem; border-bottom: 1px solid var(--rule-subtle); }
.spec-card-body   { display: flex; flex-direction: column; gap: 0.4rem; }
.spec-item        { display: flex; justify-content: space-between; align-items: center; padding: 0.2rem 0; font-size: 0.8rem; }
.spec-item span:first-child { color: var(--patina); }
.spec-item span:last-child  { color: var(--aluminum); text-align: right; font-variant-numeric: tabular-nums; }
.comm-feature     { padding: 1.25rem; border-radius: 6px; }
.comm-feature:hover { transform: translateX(3px); }
.code-feature-card { padding: 1.5rem; text-align: center; border-radius: 6px; }
.chart-container  { padding: 1.5rem; border-radius: 6px; }
.chart-container canvas { max-height: 280px; }
.perf-summary-card { padding: 1.25rem; text-align: center; border-radius: 6px; }
.safety-card      { padding: 1.25rem; text-align: center; border-radius: 6px; }
.info-section-card { padding: 1.5rem; border-radius: 6px; }
.team-card        { padding: 1.5rem; text-align: center; border-radius: 6px; }
.pioneer-card     { padding: 1.5rem; text-align: center; border-radius: 6px; }

/* Architecture left-border colors */
.arch-card.border-l-copper  { border-left-color: var(--copper) !important; }
.arch-card.border-l-patina  { border-left-color: var(--patina) !important; }

/* ============================================
   THE signature element — Flywheel Simulator
   Copper is used HERE and only here (visually)
   ============================================ */
.flywheel-sim {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
}
.flywheel-sim canvas {
    cursor: grab;
    border-radius: 50%;
    transition: filter 0.3s;
    /* display size adapts via CSS, resolution via HTML attrs */
    max-width: 100%;
    height: auto;
    aspect-ratio: 1;
}
.flywheel-sim canvas:active { cursor: grabbing; }
.flywheel-sim .sim-label {
    font-size: 0.9rem;
    color: var(--patina);
    text-align: center;
    font-family: 'Space Grotesk', 'PingFang SC', sans-serif;
}
.flywheel-sim .sim-label .rpm-val {
    font-size: 2rem;
    font-weight: 700;
    color: var(--copper);
    font-variant-numeric: tabular-nums;
    font-family: 'Space Grotesk', sans-serif;
}
.flywheel-sim .sim-label .energy-val {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--aluminum);
    font-variant-numeric: tabular-nums;
    font-family: 'Space Grotesk', sans-serif;
}
.flywheel-sim .sim-hint {
    font-size: 0.7rem;
    color: var(--patina);
    opacity: 0.65;
    transition: opacity 0.5s;
}

/* ============================================
   Section headings — subtle copper underline only
   ============================================ */
.section-heading h2 { position: relative; display: inline-block; }
.section-heading h2::after {
    content: '';
    position: absolute; bottom: -6px; left: 50%;
    transform: translateX(-50%);
    width: 36px; height: 2px;
    background: var(--copper);
    border-radius: 1px;
}

/* ============================================
   Image Placeholders
   ============================================ */
.img-placeholder {
    background: var(--steel-dark);
    border: 1px dashed var(--rule);
    border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    color: var(--patina); font-size: 0.8rem;
    overflow: hidden; transition: all 0.3s;
}
.img-placeholder:hover {
    border-color: var(--patina);
    color: var(--patina);
    background: var(--steel-surface);
}
.photo-space {
    background: var(--steel-dark);
    border: 1.5px dashed var(--rule);
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    margin: 0 auto 1rem; transition: all 0.3s;
    color: var(--patina);
}
.photo-space:hover { border-color: var(--patina); }
.pioneer-avatar, .team-avatar {
    width: 72px; height: 72px; border-radius: 50%;
    margin: 0 auto 1rem;
    display: flex; align-items: center; justify-content: center;
    background: var(--steel-dark); border: 2px solid var(--rule);
    color: var(--patina); transition: all 0.3s ease;
}
.pioneer-card:hover .pioneer-avatar,
.team-card:hover .pioneer-avatar,
.team-card:hover .team-avatar {
    border-color: var(--patina);
}

/* ============================================
   Tables
   ============================================ */
table { border-collapse: collapse; }
thead th { color: var(--aluminum) !important; font-weight: 500; }
tbody tr:hover td { background: rgba(212, 135, 74, 0.02); }

/* ============================================
   Interactive Effects (kept: tilt + typewriter)
   ============================================ */

/* 3D tilt — subtle, desktop only */
.tilt-container { perspective: 800px; transform-style: preserve-3d; }
.tilt-inner {
    transition: transform 0.1s ease-out;
    will-change: transform;
}
.tilt-inner.restoring {
    transition: transform 0.5s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}
.tilt-glow {
    position: absolute; inset: 0; border-radius: 6px;
    pointer-events: none; transition: opacity 0.3s; opacity: 0;
    background: radial-gradient(ellipse at var(--mx) var(--my),
        rgba(212, 135, 74, 0.06) 0%, transparent 60%);
    z-index: 1;
}

/* Typewriter cursor */
.typewriter-cursor {
    display: inline-block;
    width: 2px; height: 1.1em;
    background: var(--aluminum);
    margin-left: 2px; vertical-align: text-bottom;
    animation: cursorBlink 0.8s step-end infinite;
}
@keyframes cursorBlink {
    0%, 100% { opacity: 1; }
    50%      { opacity: 0; }
}

/* ============================================
   Hero chevron
   ============================================ */
@keyframes gentleBounce {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(6px); }
}
#hero .fa-chevron-down {
    animation: gentleBounce 2.5s ease-in-out infinite;
}

/* ============================================
   Back to top
   ============================================ */
#back-to-top {
    background: rgba(255,255,255,0.04);
    border: 1px solid var(--rule);
    color: var(--patina);
    box-shadow: 0 4px 16px rgba(0,0,0,0.3);
    transition: all 0.25s ease;
}
#back-to-top:hover {
    background: rgba(255,255,255,0.08);
    color: var(--aluminum);
}
#back-to-top.visible { opacity: 1 !important; visibility: visible !important; }

/* ============================================
   GitHub link
   ============================================ */
.github-link {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.85rem;
    transition: all 0.25s ease;
}
.github-link:hover {
    border-color: var(--rule) !important;
    box-shadow: 0 0 16px rgba(0,0,0,0.3);
    color: var(--aluminum);
}

/* ============================================
   Workflow dots (functional colors — muted)
   ============================================ */
.workflow-card .bg-green-500 { background-color: #5C8D6F !important; }
.workflow-card .bg-copper { background-color: var(--copper) !important; }

/* ============================================
   Hero metric readout font
   ============================================ */
#hero .font-mono {
    font-family: 'Space Grotesk', 'JetBrains Mono', 'Consolas', monospace;
}

/* ============================================
   Mobile
   ============================================ */
@media (max-width: 768px) {
    html { font-size: 14px; }
    body { text-align: center; }
    section { padding: 2.5rem 0 !important; }

    #navbar .h-16 { height: 3rem; }
    #navbar .text-lg { font-size: 0.9rem; }
    #mobile-menu a { padding: 0.6rem 1rem; font-size: 0.85rem; }

    /* Hero */
    #hero { min-height: 100vh; padding: 4rem 0.5rem 1.5rem; display: flex; align-items: center; }
    #hero h1 { font-size: 1.5rem !important; line-height: 1.2 !important; margin-bottom: 0.5rem !important; }
    #hero #hero-subtitle { font-size: 0.75rem !important; max-width: 90%; margin-bottom: 1.25rem !important; }

    /* Flywheel — scale down */
    .flywheel-sim canvas { max-width: 240px !important; }
    .flywheel-sim .sim-label { font-size: 0.75rem; }
    .flywheel-sim .sim-label .rpm-val { font-size: 1.3rem; }
    .flywheel-sim .sim-label .energy-val { font-size: 0.9rem; }
    .flywheel-sim .sim-hint { font-size: 0.65rem; }

    /* Metric readout */
    #hero .text-2xl { font-size: 1rem !important; }

    /* Section headings */
    .section-heading h2 { font-size: 1.35rem !important; }
    .section-heading p  { font-size: 0.8rem; max-width: 90%; margin-left: auto; margin-right: auto; }

    /* Cards */
    .info-card, .arch-card, .spec-card, .comm-feature,
    .code-feature-card, .safety-card, .perf-summary-card,
    .info-section-card, .team-card, .pioneer-card {
        padding: 0.85rem; border-radius: 4px;
    }
    .info-card h3, .arch-card h4, .comm-feature h4,
    .spec-card-header h3 { font-size: 0.9rem !important; }
    .info-card p, .arch-card p, .comm-feature p { font-size: 0.75rem; }

    .arch-card { text-align: left; }
    .workflow-card { width: 100%; max-width: 240px; padding: 1rem; margin: 0 auto; }
    .spec-card { text-align: left; }
    .spec-card-header .w-14 { width: 2.5rem; height: 2.5rem; }
    .spec-card-header i { font-size: 1.1rem !important; }

    /* Charts */
    .chart-container { padding: 0.75rem; }
    .chart-container canvas { max-height: 180px; }
    .chart-container h3 { font-size: 0.85rem !important; }

    /* Tables */
    table { font-size: 0.7rem; }
    th, td { padding: 0.4rem 0.5rem !important; }

    .img-placeholder { min-height: 80px; font-size: 0.7rem; }

    /* Grid collapse */
    .lg\\:grid-cols-2, .lg\\:grid-cols-3, .lg\\:grid-cols-4, .lg\\:grid-cols-5 {
        grid-template-columns: 1fr; gap: 0.6rem;
    }

    /* Footer */
    footer { padding: 1.5rem 1rem; text-align: center; }
    footer .text-sm { font-size: 0.75rem; }
    footer .github-link { padding: 0.5rem 0.75rem; font-size: 0.75rem; }
    footer .github-link i { font-size: 0.85rem; }

    #back-to-top { bottom: 0.75rem; right: 0.75rem; width: 2.25rem; height: 2.25rem; }
    .flex-wrap.items-center.justify-center { flex-direction: column; gap: 0.5rem; }

    /* Spacing */
    .mb-6  { margin-bottom: 0.75rem; } .mb-8  { margin-bottom: 1rem; }
    .mb-10 { margin-bottom: 1.25rem; }  .mb-12 { margin-bottom: 1.5rem; }
    .mb-16 { margin-bottom: 1.75rem; }
    .mt-6  { margin-top: 0.75rem; }     .mt-8  { margin-top: 1rem; }
    .mt-10 { margin-top: 1.25rem; }     .mt-12 { margin-top: 1.5rem; }
    .mt-16 { margin-top: 1.75rem; }
    .gap-4 { gap: 0.5rem; } .gap-6 { gap: 0.6rem; }
    .gap-8 { gap: 0.75rem; } .gap-12 { gap: 1rem; }
    .space-y-2 > * + * { margin-top: 0.35rem; }
    .space-y-3 > * + * { margin-top: 0.5rem; }
    .space-y-4 > * + * { margin-top: 0.6rem; }
    .space-y-5 > * + * { margin-top: 0.75rem; }
    .py-20 { padding-top: 2.5rem !important; padding-bottom: 2.5rem !important; }

    .grid-cols-2 { grid-template-columns: repeat(2, 1fr); gap: 0.4rem; }
    .max-w-7xl { padding-left: 0.75rem; padding-right: 0.75rem; }
}

@media (max-width: 480px) {
    html { font-size: 13px; }

    #hero { min-height: 100vh; padding: 3rem 0.4rem 1rem; }
    #hero h1 { font-size: 1.3rem !important; }
    #hero #hero-subtitle { font-size: 0.7rem !important; }

    .flywheel-sim canvas { max-width: 180px !important; }
    .flywheel-sim .sim-label { font-size: 0.7rem; }
    .flywheel-sim .sim-label .rpm-val { font-size: 1.1rem; }
    .flywheel-sim .sim-label .energy-val { font-size: 0.8rem; }

    #hero .text-2xl { font-size: 0.9rem !important; }

    .grid-cols-2, .sm\\:grid-cols-2 { grid-template-columns: 1fr !important; }
    #hero .grid.grid-cols-3 { gap: 0.3rem; }

    .img-placeholder { min-height: 70px; }
    .chart-container canvas { max-height: 150px; }
    section { padding: 2rem 0 !important; }
    .max-w-7xl { padding-left: 0.5rem; padding-right: 0.5rem; }
}