/*
 * WHW Design System - Shared Theme
 * What: Unified styling for light/dark themes
 * How: CSS light-dark() function with color-scheme
 * Why: Modern, DRY approach - each color defined once
 *
 * Naming Convention: BEM + CUBE CSS with prefixes
 * l-* = Layout/Composition
 * c-* = Component/Block
 * u-* = Utility
 * is-*, has-* = JS State
 * js-* = JS Hook (no styles)
 */

/* ==================== */
/* 1. TOKENS            */
/* ==================== */

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

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;600;700&family=Space+Grotesk:wght@400;600;700&display=swap');

:root {
    /* Enable both color schemes - browser respects system preference */
    color-scheme: light dark;

    /* Core colors - light-dark(light, dark) */
    /* Dark uses warmer blue-tinted grays (inspired by whw-desktop) */
    --bg: light-dark(#f5f5f5, #1a1d21);
    --bg-card: light-dark(#ffffff, #22262b);
    --bg-input: light-dark(#f5f5f5, #1a1d21);
    --text: light-dark(#1a1a1a, #e0e0e0);
    --text-dim: light-dark(#666666, #888888);
    --text-on-strong: light-dark(#f5f5f5, #e0e0e0);  /* Text on --border-strong background */
    --border: light-dark(#e0e0e0, #3a3f45);
    --border-strong: light-dark(#1a1a1a, #4a4f55);

    /* Accent - orange stays consistent, hover differs */
    --accent: #ff6b00;
    --accent-hover: light-dark(#e55f00, #ff8533);

    /* WHW Logo colors */
    --whw-accent: light-dark(#0066cc, #ff6b00);
    --whw-ring: light-dark(#1a1a1a, #525252);

    /* Flow diagram colors - same in both themes */
    --air-supply: #3b82f6;
    --air-exhaust: #8b5cf6;
    --heat: #ef4444;
    --cool: #06b6d4;
    --electric: #f59e0b;
    --data: #22c55e;

    /* Staleness indicators - same in both themes */
    --fresh: #22c55e;
    --stale-1: #84cc16;
    --stale-2: #eab308;
    --stale-3: #f97316;
    --stale-4: #ef4444;

    /* Status colors - same in both themes */
    --success: #22c55e;
    --warning: #f59e0b;
    --danger: #ef4444;

    /* Shadows - different opacity for light/dark */
    --shadow: light-dark(
        0 2px 8px rgba(0,0,0,0.1),
        0 2px 8px rgba(0,0,0,0.35)
    );
    --shadow-lg: light-dark(
        0 4px 16px rgba(0,0,0,0.15),
        0 4px 16px rgba(0,0,0,0.45)
    );

    /* Grid background opacity - subtle in both modes */
    --grid-opacity: light-dark(0.15, 0.06);

    /* Footer - same as navbar in both themes */
    --footer-bg: var(--bg-card);
    --footer-text: var(--text-dim);
    --footer-border: 1px solid var(--border);
}

/* Manual theme override via data-theme attribute */
[data-theme="light"] { color-scheme: light; }
[data-theme="dark"] { color-scheme: dark; }

/* ==================== */
/* 2. RESET & BASE      */
/* ==================== */

body {
    font-family: 'JetBrains Mono', monospace;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
}

/* ==================== */
/* 3. COMPOSITIONS (l-*)*/
/* ==================== */

/* Grid Background */
.l-grid-bg,
.grid-bg {
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 40px 40px;
    opacity: 0.15;
    z-index: 0;
    pointer-events: none;
}

/* Dark mode - even more subtle grid */
[data-theme="dark"] .l-grid-bg,
[data-theme="dark"] .grid-bg {
    opacity: 0.04;
}

/* Container */
.l-container,
.container {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Main Content Area */
.l-main,
main,
.main {
    flex: 1;
    padding: 2rem;
    max-width: 1600px;
    margin: 0 auto;
    width: 100%;
}

/* Grid Layouts */
.l-grid,
.grid { display: grid; gap: 1.5rem; }

.l-grid--2cols,
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.l-grid--3cols,
.grid-3 { grid-template-columns: repeat(3, 1fr); }

.l-grid--4cols,
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.l-grid--auto,
.grid-auto { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* Tools Grid Layout */
.l-tools-grid,
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 1.5rem;
}

/* ==================== */
/* 4. COMPONENTS (c-*)  */
/* ==================== */

/* --- Header --- */
.c-header,
header,
.header {
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid var(--border-strong);
    background: var(--bg-card);
    transition: all 0.3s;
}

.c-logo-group,
.logo-group {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.c-logo,
.logo {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--text);
    text-decoration: none;
    letter-spacing: -1px;
    transition: color 0.2s;
}

.c-logo:hover,
.logo:hover { color: var(--accent); }

/* Logo Icon - swap based on theme */
.c-logo__icon--light,
.logo-icon,
.logo-icon-light { display: block; }

.c-logo__icon--dark,
.logo-icon-dark { display: none; }

[data-theme="dark"] .c-logo__icon--light,
[data-theme="dark"] .logo-icon-light { display: none; }

[data-theme="dark"] .c-logo__icon--dark,
[data-theme="dark"] .logo-icon-dark { display: block; }

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .c-logo__icon--light,
    :root:not([data-theme="light"]) .logo-icon-light { display: none; }
    :root:not([data-theme="light"]) .c-logo__icon--dark,
    :root:not([data-theme="light"]) .logo-icon-dark { display: block; }
}

.c-page-tag,
.page-tag {
    padding: 0.25rem 0.5rem;
    background: var(--accent);
    color: white;
    font-size: 0.55rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* --- Navigation --- */
.c-nav,
.header-nav {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.c-nav__link,
.nav-link {
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.2s;
}

.c-nav__link:hover,
.c-nav__link.is-active,
.nav-link:hover,
.nav-link.active { color: var(--accent); }

/* Header Controls */
.c-header__controls,
.header-controls {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

/* --- Theme Toggle --- */
.c-theme-toggle,
.theme-toggle {
    width: 36px;
    height: 36px;
    background: var(--bg);
    border: 2px solid var(--border-strong);
    color: var(--text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.c-theme-toggle svg,
.theme-toggle svg {
    width: 18px;
    height: 18px;
}

.c-theme-toggle:hover,
.theme-toggle:hover {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

/* Theme toggle icons - show moon in light, sun in dark */
.c-theme-toggle .icon-sun,
.theme-toggle .icon-sun { display: none; }

.c-theme-toggle .icon-moon,
.theme-toggle .icon-moon { display: block; }

[data-theme="dark"] .c-theme-toggle .icon-sun,
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }

[data-theme="dark"] .c-theme-toggle .icon-moon,
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .c-theme-toggle .icon-sun,
    :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
    :root:not([data-theme="light"]) .c-theme-toggle .icon-moon,
    :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}

/* --- Language Switch --- */
.c-lang-switch,
.lang-switch {
    display: flex;
    border: 2px solid var(--border-strong);
}

.c-lang-btn,
.lang-btn {
    padding: 0.4rem 0.7rem;
    background: transparent;
    border: none;
    border-right: 2px solid var(--border-strong);
    color: var(--text);
    font-family: inherit;
    font-size: 0.6rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s;
}

.c-lang-btn:last-child,
.lang-btn:last-child { border-right: none; }

.c-lang-btn.is-active,
.lang-btn.active {
    background: var(--border-strong);
    color: var(--text-on-strong);
}

/* --- User Menu --- */
.c-user-menu,
.user-menu {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.35rem 0.75rem;
    background: var(--bg);
    border: 2px solid var(--border-strong);
    color: var(--text);
    font-size: 0.65rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
}

.c-user-menu:hover,
.user-menu:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.c-user-menu__avatar,
.user-avatar {
    width: 20px;
    height: 20px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.5rem;
}

/* --- Page Header --- */
.c-page-header,
.page-header {
    margin-bottom: 2rem;
}

.c-page-header__title,
.page-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.75rem;
    font-weight: 700;
}

.c-page-header__desc,
.page-desc {
    font-size: 0.75rem;
    color: var(--text-dim);
    margin-top: 0.25rem;
}

/* --- Cards --- */
.c-card,
.card {
    background: var(--bg-card);
    border: 3px solid var(--border-strong);
    padding: 1.5rem;
    position: relative;
    transition: all 0.2s;
}

.c-card:hover,
.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.c-card::before,
.card::before {
    content: attr(data-id);
    position: absolute;
    top: -0.6rem;
    left: 0.75rem;
    background: var(--bg);
    padding: 0 0.4rem;
    font-size: 0.5rem;
    color: var(--text-dim);
    letter-spacing: 1px;
}

.c-card__header,
.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 2px dashed var(--border);
}

.c-card__icon,
.card-icon {
    width: 45px;
    height: 45px;
    background: var(--bg);
    border: 2px solid var(--border-strong);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
    color: var(--accent);
}

.c-card__icon svg,
.card-icon svg {
    width: 24px;
    height: 24px;
}

.c-card__title,
.card-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.c-card__subtitle,
.card-subtitle {
    font-size: 0.65rem;
    color: var(--text-dim);
    margin-top: 0.25rem;
}

/* --- Calculator Card --- */
.c-calc-card,
.calc-card {
    background: var(--bg-card);
    border: 1px solid var(--border-strong);
    padding: 1.5rem;
    position: relative;
}

.c-calc-card::before,
.calc-card::before {
    content: attr(data-id);
    position: absolute;
    top: -0.6rem;
    left: 1rem;
    background: var(--bg);
    padding: 0.2rem 0.6rem;
    font-size: 0.55rem;
    color: var(--text-dim);
    letter-spacing: 1px;
}

/* --- Forms --- */
.c-form__group,
.form-group {
    margin-bottom: 1rem;
}

.c-form__label,
.form-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.4rem;
    font-size: 0.65rem;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.c-form__input,
.c-form__select,
.form-input,
.form-select {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-input);
    border: 2px solid var(--border-strong);
    color: var(--text);
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.2s;
}

.c-form__input:focus,
.c-form__select:focus,
.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(255, 107, 0, 0.15);
}

.c-form__input::placeholder,
.form-input::placeholder {
    color: var(--text-dim);
    opacity: 0.6;
}

/* --- Input Group (Tools) --- */
.c-input-group,
.input-group {
    margin-bottom: 1rem;
}

.c-input__label,
.input-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.4rem;
    font-size: 0.65rem;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.c-input__unit,
.input-unit {
    color: var(--accent);
    font-weight: 700;
}

.c-input,
.input-field {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg);
    border: 2px solid var(--border-strong);
    color: var(--text);
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.2s;
}

.c-input:focus,
.input-field:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(255, 107, 0, 0.1);
}

.c-input::placeholder,
.input-field::placeholder {
    color: var(--border);
}

.c-input-row,
.input-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
}

/* --- Result Display --- */
.c-result,
.result-display {
    background: var(--bg);
    border: 3px solid var(--success);
    padding: 1rem;
    margin-top: 1rem;
    position: relative;
}

.c-result::before,
.result-display::before {
    content: 'VYSLEDEK';
    position: absolute;
    top: -0.6rem;
    left: 0.75rem;
    background: var(--bg-card);
    padding: 0 0.4rem;
    font-size: 0.55rem;
    color: var(--success);
    font-weight: 700;
    letter-spacing: 1px;
}

.c-result__value,
.result-value {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 2rem;
    font-weight: 700;
    color: var(--success);
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
}

.c-result__unit,
.result-unit {
    font-size: 1rem;
    color: var(--text-dim);
}

.c-result__status,
.result-status {
    margin-top: 0.5rem;
    font-size: 0.65rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.c-status-dot,
.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 2px;
}

.c-status-dot--ok,
.status-ok { background: var(--success); }

.c-status-dot--warn,
.status-warn { background: var(--warning); }

.c-status-dot--error,
.status-error { background: var(--danger); }

/* --- Formula Box --- */
.c-formula,
.formula-box {
    background: var(--bg);
    border-left: 4px solid var(--accent);
    padding: 0.75rem 1rem;
    margin-top: 1rem;
    font-size: 0.65rem;
    color: var(--text-dim);
}

.c-formula code,
.formula-box code {
    color: var(--text);
    font-weight: 600;
}

/* --- Reference Table --- */
.c-ref-table,
.ref-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.7rem;
    margin-top: 1rem;
}

.c-ref-table th,
.c-ref-table td,
.ref-table th,
.ref-table td {
    padding: 0.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.c-ref-table th,
.ref-table th {
    color: var(--accent);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 0.6rem;
}

/* --- Buttons --- */
.c-btn,
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--border-strong);
    border: 2px solid var(--border-strong);
    color: var(--text-on-strong);
    font-family: inherit;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
}

.c-btn:hover,
.btn:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.c-btn--primary,
.btn-primary {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.c-btn--primary:hover,
.btn-primary:hover {
    background: var(--accent-hover);
    border-color: var(--accent-hover);
}

.c-btn--outline,
.btn-outline {
    background: transparent;
    color: var(--text);
}

.c-btn--outline:hover,
.btn-outline:hover {
    background: var(--border-strong);
    color: var(--text-on-strong);
}

.c-btn--cta,
.cta-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--accent);
    color: white;
    text-decoration: none;
    font-weight: 700;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    border: 3px solid var(--accent);
    transition: all 0.2s;
}

.c-btn--cta:hover,
.cta-btn:hover {
    background: var(--border-strong);
    border-color: var(--border-strong);
    color: var(--text-on-strong);
}

/* --- Footer --- */
.c-footer,
footer,
.footer {
    padding: 1.5rem 2rem;
    background: var(--footer-bg);
    color: var(--footer-text);
    border-top: var(--footer-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.c-footer__info,
.footer-info {
    font-size: 0.6rem;
    opacity: 0.8;
}

.c-footer__links,
.footer-links {
    display: flex;
    gap: 1.5rem;
}

.c-footer__links a,
.footer-links a {
    color: inherit;
    text-decoration: none;
    font-size: 0.65rem;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.c-footer__links a:hover,
.footer-links a:hover { opacity: 1; }

.c-footer__version {
    font-size: 0.55rem;
    opacity: 0.5;
    font-family: 'JetBrains Mono', monospace;
    letter-spacing: 1px;
}

/* --- Index Page - Label Card --- */
.c-main-label,
.main-label {
    background: var(--bg-card);
    border: 3px solid var(--border-strong);
    padding: 2rem;
    position: relative;
}

.c-main-label::before,
.main-label::before {
    content: 'WHW-SYS-001';
    position: absolute;
    top: -0.7rem;
    left: 1rem;
    background: var(--bg);
    padding: 0 0.5rem;
    font-size: 0.6rem;
    color: var(--text-dim);
    letter-spacing: 2px;
}

.c-label__header,
.label-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px dashed var(--border);
}

.c-label__title,
.label-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 4rem;
    font-weight: 700;
    line-height: 0.9;
    letter-spacing: -2px;
}

.c-label__barcode,
.c-label__codes,
.label-barcode {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.c-barcode,
.barcode {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.25rem;
}

.c-barcode__svg {
    width: 120px;
    height: 40px;
    color: var(--border-strong);
}

.c-barcode__text,
.barcode-text {
    font-size: 0.5rem;
    color: var(--text-dim);
    letter-spacing: 2px;
    font-weight: 600;
}

/* QR Code */
.c-qrcode {
    display: block;
    padding: 4px;
    background: #ffffff;
    border: 2px solid var(--border-strong);
    transition: border-color 0.2s, transform 0.2s;
}

.c-qrcode:hover {
    border-color: var(--accent);
    transform: scale(1.05);
}

.c-qrcode__img {
    display: block;
    width: 52px;
    height: 52px;
}

.c-label__subtitle,
.label-subtitle {
    font-size: 0.8rem;
    color: var(--text-dim);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.c-label__tags,
.label-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.c-tag,
.tag {
    padding: 0.35rem 0.7rem;
    border: 2px solid var(--border-strong);
    font-size: 0.55rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.c-tag--highlight,
.tag.highlight {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.c-logo-tag,
.logo-tag {
    padding: 0.25rem 0.5rem;
    background: var(--accent);
    color: white;
    font-size: 0.55rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* --- Index Page - Circuit Section --- */
.c-circuit,
.circuit-section {
    position: relative;
    height: 400px;
}

.c-circuit__line,
.circuit-line {
    position: absolute;
    background: var(--border-strong);
}

.c-circuit__line--vertical,
.circuit-line.vertical { width: 3px; }

.c-circuit__line--horizontal,
.circuit-line.horizontal { height: 3px; }

.c-circuit__line--main,
.line-main {
    left: 50%;
    top: 0;
    height: 100%;
    transform: translateX(-50%);
}

.c-circuit__line--h1,
.line-h1 { top: 60px; left: 10%; width: 40%; }

.c-circuit__line--h2,
.line-h2 { top: 120px; left: 50%; width: 40%; }

.c-circuit__line--h3,
.line-h3 { top: 260px; left: 10%; width: 40%; }

.c-circuit__line--h4,
.line-h4 { top: 340px; left: 50%; width: 40%; }

.c-circuit__junction,
.junction {
    position: absolute;
    width: 12px;
    height: 12px;
    background: var(--border-strong);
    border-radius: 50%;
    transform: translate(-50%, -50%);
}

.c-circuit__junction--1,
.junction-1 { top: 60px; left: 50%; }

.c-circuit__junction--2,
.junction-2 { top: 120px; left: 50%; }

.c-circuit__junction--3,
.junction-3 { top: 260px; left: 50%; }

.c-circuit__junction--4,
.junction-4 { top: 340px; left: 50%; }

.c-circuit__node,
.node {
    position: absolute;
    background: var(--bg-card);
    border: 3px solid var(--border-strong);
    padding: 0.8rem 1.2rem;
    transition: all 0.2s;
}

.c-circuit__node:hover,
.node:hover {
    background: var(--border-strong);
    color: var(--text-on-strong);
}

.c-circuit__node:hover .c-circuit__node-desc,
.node:hover .node-desc {
    color: var(--text-on-strong);
    opacity: 0.7;
}

.c-circuit__node-letter,
.node-letter {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.8rem;
    font-weight: 700;
    line-height: 1;
}

.c-circuit__node-word,
.node-word {
    font-size: 0.6rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--accent);
    font-weight: 700;
}

.c-circuit__node-desc,
.node-desc {
    font-size: 0.55rem;
    color: var(--text-dim);
    margin-top: 0.3rem;
    max-width: 120px;
}

.c-circuit__node--w1,
.node-w1 { top: 40px; left: 0; }

.c-circuit__node--h,
.node-h { top: 100px; right: 0; }

.c-circuit__node--w2,
.node-w2 { top: 240px; left: 0; }

.c-circuit__node--center,
.node-center {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 1rem 1.5rem;
    border-color: var(--accent);
    border-width: 4px;
    z-index: 10;
    text-align: center;
}

.c-circuit__node--center .c-circuit__node-letter,
.node-center .node-letter {
    font-size: 2.2rem;
    color: var(--accent);
}

.c-circuit__cta,
.circuit-cta {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}

/* Mobile WHW */
.c-mobile-whw,
.mobile-whw {
    display: none;
}

.c-mobile-whw__node,
.mobile-whw .mnode {
    flex: 1;
    padding: 1rem;
    border: 2px solid var(--border-strong);
    text-align: center;
}

.c-mobile-whw__letter,
.mobile-whw .mnode-letter {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
}

.c-mobile-whw__word,
.mobile-whw .mnode-word {
    font-size: 0.55rem;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* ==================== */
/* 5. UTILITIES (u-*)   */
/* ==================== */

.u-text--success,
.text-success { color: var(--success); }

.u-text--warning,
.text-warning { color: var(--warning); }

.u-text--danger,
.text-danger { color: var(--danger); }

.u-text--accent,
.text-accent { color: var(--accent); }

.u-text--dim,
.text-dim { color: var(--text-dim); }

.u-mt--1,
.mt-1 { margin-top: 0.5rem; }

.u-mt--2,
.mt-2 { margin-top: 1rem; }

.u-mt--3,
.mt-3 { margin-top: 1.5rem; }

.u-mb--1,
.mb-1 { margin-bottom: 0.5rem; }

.u-mb--2,
.mb-2 { margin-bottom: 1rem; }

.u-mb--3,
.mb-3 { margin-bottom: 1.5rem; }

/* ==================== */
/* 6. RESPONSIVE        */
/* ==================== */

@media (max-width: 900px) {
    main.index-main {
        grid-template-columns: 1fr;
        padding: 1.5rem;
        gap: 2rem;
    }

    .c-circuit,
    .circuit-section {
        height: 300px;
    }

    .c-label__title,
    .label-title {
        font-size: 3rem;
    }

    .c-circuit__node-desc,
    .node-desc {
        display: none;
    }
}

@media (max-width: 768px) {
    .c-header,
    header,
    .header {
        padding: 1rem;
    }

    .c-nav .c-nav__link,
    .header-nav .nav-link {
        display: none;
    }

    .l-main,
    main,
    .main {
        padding: 1rem;
    }

    .l-grid--2cols,
    .l-grid--3cols,
    .l-grid--4cols,
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }

    .l-tools-grid,
    .tools-grid {
        grid-template-columns: 1fr;
    }

    .c-input-row,
    .input-row {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 500px) {
    .c-circuit,
    .circuit-section {
        display: none;
    }

    .c-mobile-whw,
    .mobile-whw {
        display: flex;
        gap: 0.5rem;
        margin-top: 1.5rem;
    }
}