@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800&family=Plus+Jakarta+Sans:wght@300;400;500;600;700&display=swap');

:root {
    --bg-primary: #0a0f1d;
    --bg-secondary: #131a30;
    --bg-card: rgba(25, 35, 60, 0.65);
    --border-color: rgba(255, 255, 255, 0.08);
    --accent-blue: #3b82f6;
    --accent-cyan: #06b6d4;
    --accent-teal: #10b981;
    --accent-glow: rgba(59, 130, 246, 0.15);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Plus Jakarta Sans', sans-serif;
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --radius-lg: 16px;
    --radius-md: 12px;
    --radius-sm: 8px;
    --transition-smooth: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    overflow-x: hidden;
    line-height: 1.6;
}

/* Bilingual Toggle Rules */
body.lang-en .lang-zh {
    display: none !important;
}
body:not(.lang-en) .lang-en {
    display: none !important;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
    background: var(--bg-secondary);
    border-radius: 4px;
    border: 2px solid var(--bg-primary);
}
::-webkit-scrollbar-thumb:hover {
    background: var(--accent-blue);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    letter-spacing: -0.02em;
}

/* Layout Utilities */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

.glass-card {
    background: var(--bg-card);
    backdrop-filter: blur(12px) saturate(180%);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--glass-shadow);
    transition: var(--transition-smooth);
}

.glass-card:hover {
    border-color: rgba(59, 130, 246, 0.3);
    box-shadow: 0 12px 40px 0 rgba(59, 130, 246, 0.1);
}

/* Header & Navigation */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    background: rgba(10, 15, 29, 0.7);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.logo {
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 22px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    width: 26px;
    height: 26px;
    fill: var(--accent-cyan);
}

.nav-links {
    display: flex;
    gap: 24px;
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 14px;
    transition: var(--transition-smooth);
    position: relative;
    padding: 8px 0;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue));
    transition: var(--transition-smooth);
}

.nav-links a:hover {
    color: var(--text-primary);
}

.nav-links a:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    padding: 160px 0 100px 0;
    position: relative;
    overflow: hidden;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-bg-glow {
    position: absolute;
    top: -20%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.15) 0%, rgba(59, 130, 246, 0.05) 50%, transparent 100%);
    filter: blur(80px);
    z-index: -1;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
    align-items: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-radius: 30px;
    font-size: clamp(11px, 2.5vw, 13px);
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 24px;
    white-space: nowrap;
    max-width: 100%;
}

.hero-badge .hero-badge-dot {
    width: 6px;
    height: 6px;
    background: var(--accent-cyan);
    border-radius: 50%;
    display: inline-block;
    box-shadow: 0 0 10px var(--accent-cyan);
    flex-shrink: 0;
}

.hero h1 {
    font-size: clamp(28px, 6vw, 52px);
    line-height: 1.15;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #ffffff 50%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 17px;
    color: var(--text-secondary);
    margin-bottom: 40px;
    max-width: 580px;
}

.hero-cta {
    display: flex;
    gap: 16px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 13px 26px;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-decoration: none;
    font-size: 15px;
    cursor: pointer;
    transition: var(--transition-smooth);
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-cyan));
    color: #ffffff;
    box-shadow: 0 4px 20px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 28px rgba(59, 130, 246, 0.45);
}

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

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--text-secondary);
}

/* Water Flow Visual in Hero */
.hero-visual-wrapper {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-circle {
    width: 320px;
    height: 320px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, rgba(6, 182, 212, 0.05) 70%, transparent 100%);
    border: 1px dashed rgba(59, 130, 246, 0.3);
    position: relative;
    animation: rotateDashed 20s linear infinite;
    display: flex;
    justify-content: center;
    align-items: center;
}

@keyframes rotateDashed {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.hero-softener-mockup {
    position: absolute;
    width: 140px;
    height: 240px;
    background: linear-gradient(180deg, rgba(30, 41, 59, 0.8) 0%, rgba(15, 23, 42, 0.95) 100%);
    border: 2px solid rgba(59, 130, 246, 0.4);
    border-radius: 20px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5), inset 0 0 20px rgba(59, 130, 246, 0.2);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 15px;
    z-index: 2;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
    100% { transform: translateY(0px); }
}

.hero-softener-valve {
    height: 30px;
    width: 80%;
    margin: 0 auto;
    background: linear-gradient(90deg, #475569, #64748b, #475569);
    border-radius: 8px;
    border-bottom: 2px solid rgba(59, 130, 246, 0.5);
    position: relative;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

.hero-softener-valve::after {
    content: '';
    position: absolute;
    width: 10px;
    height: 10px;
    background: var(--accent-cyan);
    border-radius: 50%;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 0 10px var(--accent-cyan);
}

.hero-softener-tank {
    flex-grow: 1;
    margin: 15px 0;
    border-radius: 10px;
    background: rgba(10, 15, 29, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.05);
    position: relative;
    overflow: hidden;
}

.hero-water-waves {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 70%;
    background: linear-gradient(180deg, rgba(6, 182, 212, 0.3) 0%, rgba(59, 130, 246, 0.5) 100%);
    border-top: 1px solid rgba(255,255,255,0.4);
    animation: waveRise 4s ease-in-out infinite alternate;
}

@keyframes waveRise {
    0% { height: 60%; }
    100% { height: 75%; }
}

/* Sections Global */
.section {
    padding: 90px 0;
    position: relative;
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
    position: relative;
}

.section-subtitle {
    font-size: 13px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--accent-cyan);
    margin-bottom: 12px;
    display: block;
}

.section-title {
    font-size: 34px;
    background: linear-gradient(135deg, #ffffff 60%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 16px;
}

.section-desc {
    color: var(--text-secondary);
    font-size: 15px;
    max-width: 650px;
    margin: 0 auto;
}

/* Principle & Micro Canvas Section */
.principle-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    align-items: start;
}

.canvas-container {
    position: relative;
    width: 100%;
    height: 420px;
    border-radius: var(--radius-lg);
    background: radial-gradient(circle at center, #15223e 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

#ionExchangeCanvas {
    width: 100%;
    height: 100%;
    display: block;
}

.canvas-overlay {
    position: absolute;
    bottom: 20px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-between;
    background: rgba(10, 15, 29, 0.85);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 11px;
    color: var(--text-secondary);
}

.legend-color {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.legend-ca-mg {
    background: linear-gradient(135deg, #ff4d4d, #f59e0b);
    box-shadow: 0 0 6px #ff4d4d;
}

.legend-na {
    background: linear-gradient(135deg, #38bdf8, #3b82f6);
    box-shadow: 0 0 6px #38bdf8;
}

.legend-resin {
    background: radial-gradient(circle, #fbbf24 30%, #b45309 100%);
    border-radius: 50%;
    width: 14px;
    height: 14px;
}

/* Explanation Cards */
.explanation-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.explanation-card {
    padding: 20px;
    display: flex;
    gap: 18px;
    align-items: flex-start;
}

.step-number {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: rgba(59, 130, 246, 0.15);
    border: 1px solid rgba(59, 130, 246, 0.3);
    color: var(--accent-cyan);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-family: var(--font-heading);
    flex-shrink: 0;
    font-size: 14px;
}

.explanation-card h3 {
    font-size: 17px;
    margin-bottom: 6px;
    color: var(--text-primary);
}

.explanation-card p {
    color: var(--text-secondary);
    font-size: 13.5px;
    line-height: 1.5;
}

/* Component Anatomy Section */
.anatomy-layout {
    display: grid;
    grid-template-columns: 1fr 1.1fr;
    gap: 40px;
    align-items: center;
}

.anatomy-viewer {
    position: relative;
    height: 520px;
    background: linear-gradient(180deg, #12182c 0%, #0a0f1d 100%);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

/* Vector-based Softener Interactive Diagram */
.softener-schematic {
    width: 280px;
    height: 460px;
    position: relative;
}

.schematic-valve {
    position: absolute;
    top: 20px;
    left: 70px;
    width: 140px;
    height: 60px;
    background: linear-gradient(90deg, #475569 0%, #cbd5e1 50%, #475569 100%);
    border: 2px solid #334155;
    border-radius: 12px;
    cursor: pointer;
    z-index: 10;
    transition: var(--transition-smooth);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 11px;
    font-weight: 800;
    color: #0f172a;
    text-align: center;
}

.schematic-valve.active, .schematic-valve:hover {
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.8);
    border-color: var(--accent-blue);
}

.schematic-resin-tank {
    position: absolute;
    top: 75px;
    left: 90px;
    width: 100px;
    height: 350px;
    background: rgba(30, 41, 59, 0.4);
    border: 3px solid #64748b;
    border-radius: 30px 30px 10px 10px;
    cursor: pointer;
    overflow: hidden;
    z-index: 5;
    transition: var(--transition-smooth);
}

.schematic-resin-tank.active, .schematic-resin-tank:hover {
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.6);
    border-color: var(--accent-blue);
}

.schematic-resin-beads {
    position: absolute;
    bottom: 30px;
    left: 5px;
    width: 84px;
    height: 220px;
    background-image: radial-gradient(rgba(251, 191, 36, 0.7) 15%, transparent 20%);
    background-size: 8px 8px;
    border-radius: 8px;
    opacity: 0.85;
}

.schematic-riser-pipe {
    position: absolute;
    top: 0;
    left: 42px;
    width: 10px;
    height: 320px;
    background: linear-gradient(90deg, #94a3b8, #e2e8f0, #94a3b8);
    border: 1px solid #475569;
    z-index: 6;
}

.schematic-distributor {
    position: absolute;
    bottom: 5px;
    left: 27px;
    width: 40px;
    height: 25px;
    background: #475569;
    border-radius: 4px;
    border: 1px solid #cbd5e1;
    z-index: 7;
}

.schematic-brine-tank {
    position: absolute;
    top: 130px;
    left: 10px;
    width: 70px;
    height: 290px;
    background: rgba(51, 65, 85, 0.5);
    border: 3px solid #64748b;
    border-radius: 12px;
    cursor: pointer;
    z-index: 4;
    transition: var(--transition-smooth);
}

.schematic-brine-tank.active, .schematic-brine-tank:hover {
    box-shadow: 0 0 20px rgba(6, 182, 212, 0.6);
    border-color: var(--accent-cyan);
}

.schematic-salt-grid {
    position: absolute;
    bottom: 40px;
    left: 5px;
    right: 5px;
    height: 100px;
    background: linear-gradient(0deg, #f8fafc 50%, transparent 100%);
    border-radius: 4px;
    opacity: 0.7;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    padding-bottom: 20px;
    font-size: 10px;
    font-weight: 700;
    color: #475569;
    text-align: center;
}

.schematic-brine-well {
    position: absolute;
    top: 20px;
    right: 5px;
    width: 15px;
    height: 250px;
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 2px;
}

.schematic-bypass-valve {
    position: absolute;
    top: 0px;
    left: 200px;
    width: 60px;
    height: 40px;
    background: linear-gradient(180deg, #dc2626 0%, #991b1b 100%);
    border: 1px solid #7f1d1d;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition-smooth);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 9px;
    font-weight: 700;
    color: #ffffff;
    text-align: center;
}

.schematic-bypass-valve.active, .schematic-bypass-valve:hover {
    box-shadow: 0 0 15px rgba(220, 38, 38, 0.7);
    border-color: #f87171;
}

.schematic-brine-line {
    position: absolute;
    top: 50px;
    left: 30px;
    width: 50px;
    height: 100px;
    border-left: 2px dashed var(--accent-cyan);
    border-top: 2px dashed var(--accent-cyan);
    border-radius: 8px 0 0 0;
    pointer-events: none;
    z-index: 3;
}

.anatomy-details {
    padding-left: 10px;
}

.anatomy-info-card {
    padding: 28px;
    min-height: 300px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.anatomy-info-card h3 {
    font-size: 22px;
    color: var(--accent-cyan);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.anatomy-info-card p {
    color: var(--text-secondary);
    font-size: 14.5px;
    line-height: 1.6;
    margin-bottom: 18px;
}

.anatomy-spec-list {
    list-style: none;
}

.anatomy-spec-list li {
    font-size: 13.5px;
    color: var(--text-primary);
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.anatomy-spec-list li::before {
    content: '✦';
    color: var(--accent-blue);
}

.anatomy-hint {
    margin-top: 20px;
    color: var(--text-muted);
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: 6px;
}

/* Regeneration Flow Section */
.regen-tabs {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 12px;
    margin-bottom: 30px;
}

.regen-tab-btn {
    padding: 14px 10px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    text-align: center;
    transition: var(--transition-smooth);
}

.regen-tab-btn h4 {
    font-size: 14px;
    margin-bottom: 4px;
    color: var(--text-primary);
}

.regen-tab-btn span {
    font-size: 11px;
    color: var(--text-secondary);
}

.regen-tab-btn:hover, .regen-tab-btn.active {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.15), rgba(6, 182, 212, 0.05));
    border-color: var(--accent-cyan);
    box-shadow: 0 0 15px rgba(6, 182, 212, 0.1);
}

.regen-tab-btn.active h4 {
    color: var(--accent-cyan);
}

.regen-display-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 40px;
    align-items: center;
}

.regen-animation-box {
    position: relative;
    height: 440px;
    background: linear-gradient(180deg, #12182c 0%, #0a0f1d 100%);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
}

.flow-svg {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
}

.flow-pipe-path {
    fill: none;
    stroke: rgba(255, 255, 255, 0.1);
    stroke-width: 6px;
    stroke-linecap: round;
}

.flow-active-path {
    fill: none;
    stroke-width: 8px;
    stroke-linecap: round;
    stroke-dasharray: 12, 12;
    animation: flowDash 2s linear infinite;
    display: none;
}

.flow-active-path.flow-active {
    display: inline !important;
}

.flow-active-path.hard-water {
    stroke: #ff9d00;
}

.flow-active-path.soft-water {
    stroke: var(--accent-cyan);
}

.flow-active-path.brine-water {
    stroke: #10b981;
}

.flow-active-path.drain-water {
    stroke: #ef4444;
}

@keyframes flowDash {
    from {
        stroke-dashoffset: 0;
    }
    to {
        stroke-dashoffset: -24;
    }
}

.regen-info-panel {
    padding: 10px;
}

.regen-badge {
    display: inline-block;
    padding: 6px 12px;
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.2);
    color: var(--accent-teal);
    border-radius: 30px;
    font-size: 12.5px;
    font-weight: 600;
    margin-bottom: 20px;
}

.regen-info-panel h3 {
    font-size: 26px;
    margin-bottom: 14px;
    color: #ffffff;
}

.regen-info-panel p {
    color: var(--text-secondary);
    font-size: 14.5px;
    line-height: 1.6;
    margin-bottom: 24px;
}

.regen-meta-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.regen-stat-card {
    padding: 14px;
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
}

.regen-stat-label {
    font-size: 11.5px;
    color: var(--text-muted);
    display: block;
    margin-bottom: 4px;
}

.regen-stat-value {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-primary);
}

/* Control Valves Comparison Section */
.valve-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.valve-card {
    padding: 28px 20px;
    display: flex;
    flex-direction: column;
}

.valve-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.valve-brand {
    font-size: 19px;
    color: var(--accent-cyan);
}

.valve-origin {
    font-size: 11px;
    background: rgba(255,255,255,0.05);
    padding: 4px 8px;
    border-radius: 20px;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.valve-diagram {
    height: 180px;
    background: rgba(0,0,0,0.15);
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    padding: 10px;
}

.valve-features {
    list-style: none;
    margin-bottom: 24px;
    flex-grow: 1;
}

.valve-features li {
    font-size: 13.5px;
    color: var(--text-secondary);
    margin-bottom: 10px;
    display: flex;
    align-items: flex-start;
    gap: 8px;
    line-height: 1.5;
}

.valve-features li::before {
    content: '✓';
    color: var(--accent-teal);
    font-weight: bold;
    flex-shrink: 0;
    margin-top: 2px;
}

.valve-score-row {
    border-top: 1px solid var(--border-color);
    padding-top: 16px;
}

.valve-score-label {
    display: flex;
    justify-content: space-between;
    font-size: 12.5px;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.valve-score-bar {
    height: 5px;
    background: rgba(255,255,255,0.05);
    border-radius: 3px;
    overflow: hidden;
}

.valve-score-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-cyan));
    border-radius: 3px;
}

/* Competitor & Brands Section */
.competitors-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.brand-radar-container {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    padding: 24px;
}

#brandRadarChart {
    width: 100%;
    max-height: 380px;
}

.brand-selector {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.brand-card-small {
    padding: 16px;
    cursor: pointer;
    text-align: left;
    position: relative;
    overflow: hidden;
}

.brand-card-small.active {
    border-color: var(--accent-blue);
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(6, 182, 212, 0.02));
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.15);
}

.brand-card-small h3 {
    font-size: 16px;
    margin-bottom: 4px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.brand-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}

.brand-eco .brand-dot { background-color: #3b82f6; }
.brand-bwt .brand-dot { background-color: #ec4899; }
.brand-runxin .brand-dot { background-color: #10b981; }
.brand-others .brand-dot { background-color: #f59e0b; }

.brand-card-small p {
    font-size: 11.5px;
    color: var(--text-secondary);
}

.brand-detal-pane {
    margin-top: 20px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.brand-detail-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 13px;
}

.brand-detail-label {
    color: var(--text-secondary);
}

.brand-detail-value {
    color: var(--text-primary);
    font-weight: 600;
}

/* Buying Calculator Section */
.calc-grid {
    display: grid;
    grid-template-columns: 0.9fr 1.1fr;
    gap: 32px;
}

.calc-form {
    padding: 28px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 13.5px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.input-range-container {
    display: flex;
    align-items: center;
    gap: 16px;
}

input[type="range"] {
    flex-grow: 1;
    accent-color: var(--accent-blue);
    background: rgba(255, 255, 255, 0.08);
    height: 6px;
    border-radius: 3px;
    cursor: pointer;
}

.range-val {
    width: 45px;
    text-align: right;
    font-weight: 700;
    font-size: 16px;
    color: var(--accent-cyan);
    font-family: var(--font-heading);
}

.radio-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.radio-card {
    position: relative;
    border: 1px solid var(--border-color);
    background: rgba(255, 255, 255, 0.02);
    border-radius: var(--radius-md);
    padding: 10px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.radio-card input {
    position: absolute;
    opacity: 0;
}

.radio-card:hover {
    border-color: rgba(59, 130, 246, 0.3);
}

.radio-card.active {
    border-color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.1);
    color: #ffffff;
}

.radio-card h4 {
    font-size: 14px;
    margin-bottom: 2px;
}

.radio-card span {
    font-size: 10px;
    color: var(--text-secondary);
}

.preset-hardness-btn {
    padding: 6px 12px;
    font-size: 11px;
    border-radius: 20px;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    text-decoration: none;
    transition: var(--transition-smooth);
    background: rgba(255,255,255,0.02);
}

.preset-hardness-btn:hover {
    border-color: var(--accent-blue);
    color: #ffffff;
    background: rgba(59, 130, 246, 0.1);
}

/* Calculator Results */
.calc-results {
    padding: 28px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.results-header {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 16px;
    margin-bottom: 20px;
}

.results-title {
    font-size: 19px;
    color: var(--accent-cyan);
    margin-bottom: 4px;
}

.results-metric-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-bottom: 20px;
}

.result-card-stat {
    padding: 12px;
    background: rgba(0,0,0,0.15);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
}

.result-stat-num {
    font-size: 22px;
    font-weight: 800;
    color: #ffffff;
    font-family: var(--font-heading);
    margin-bottom: 2px;
    display: block;
}

.result-stat-num span {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-left: 2px;
}

.result-stat-desc {
    font-size: 11.5px;
    color: var(--text-muted);
}

.recommendations-box {
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
}

.recommendations-box h4 {
    font-size: 15px;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.rec-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px;
    background: rgba(255,255,255,0.02);
    border-radius: var(--radius-sm);
    margin-bottom: 8px;
    border: 1px solid var(--border-color);
}

.rec-label {
    font-size: 13px;
    color: var(--text-secondary);
}

.rec-value {
    font-weight: 600;
    color: var(--accent-cyan);
    font-size: 13px;
}

/* Footer styling */
footer {
    padding: 50px 0 35px 0;
    background: #060913;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.footer-logo {
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 18px;
    color: #ffffff;
}

.footer-logo span {
    color: var(--accent-cyan);
}

.footer-links {
    display: flex;
    gap: 20px;
}

.footer-links a {
    color: var(--text-muted);
    font-size: 13.5px;
    text-decoration: none;
    transition: var(--transition-smooth);
}

.footer-links a:hover {
    color: var(--accent-blue);
}

.footer-copyright {
    text-align: center;
    color: var(--text-muted);
    font-size: 11.5px;
    border-top: 1px solid rgba(255,255,255,0.05);
    padding-top: 16px;
}

/* Responsive adjustments */
@media (max-width: 1024px) {
    .hero-grid, .principle-grid, .anatomy-layout, .regen-display-grid, .competitors-grid, .calc-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .hero {
        padding: 120px 0 60px 0;
    }
    .hero-visual-wrapper {
        order: -1;
        margin-bottom: 20px;
    }
    .valve-grid {
        grid-template-columns: 1fr;
    }
    .regen-tabs {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 640px) {
    .regen-tabs {
        grid-template-columns: repeat(2, 1fr);
    }
    .radio-cards {
        grid-template-columns: 1fr;
    }
    .hero h1 {
        font-size: 36px;
    }
    .nav-links {
        display: none;
    }
}

/* Valve Simulator Styles */
.sim-svg {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.sim-flow-path-internal {
    fill: none;
    stroke-dasharray: 8, 8;
    stroke-width: 5px;
    stroke-linecap: round;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.sim-flow-path-internal.flow-active {
    opacity: 0.95;
    animation: simFlowDash 1.2s linear infinite;
}

@keyframes simFlowDash {
    from {
        stroke-dashoffset: 0;
    }
    to {
        stroke-dashoffset: -16;
    }
}

.simulator-switcher .btn.active,
.simulator-cycle-selector .btn.active {
    background: linear-gradient(135deg, rgba(6, 182, 212, 0.25), rgba(59, 130, 246, 0.15)) !important;
    border-color: var(--accent-cyan) !important;
    color: #ffffff !important;
    box-shadow: 0 0 12px rgba(6, 182, 212, 0.15);
}

.valve-simulator-card {
    border-color: rgba(6, 182, 212, 0.2) !important;
}

/* Scrollbar tuning for explanation-list in valve components */
.explanation-list::-webkit-scrollbar {
    width: 6px;
}
.explanation-list::-webkit-scrollbar-track {
    background: transparent;
}
.explanation-list::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.06);
    border-radius: 3px;
}
.explanation-list::-webkit-scrollbar-thumb:hover {
    background: var(--accent-cyan);
}