/* ===================================
   AMPERAGE CALCULATOR - PREMIUM DESIGN
   =================================== */

/* --- CSS Custom Properties --- */
:root {
    /* Colors */
    --bg-primary: #050510;
    --bg-secondary: #0a0a1f;
    --bg-card: rgba(15, 15, 40, 0.7);
    --bg-card-hover: rgba(20, 20, 50, 0.85);
    --bg-input: rgba(10, 10, 30, 0.9);

    --text-primary: #e8eaf6;
    --text-secondary: #9ca3c7;
    --text-muted: #5a5f7d;

    --accent-blue: #00d4ff;
    --accent-blue-dim: rgba(0, 212, 255, 0.15);
    --accent-purple: #7c3aed;
    --accent-purple-dim: rgba(124, 58, 237, 0.15);
    --accent-gold: #ffd700;
    --accent-gold-dim: rgba(255, 215, 0, 0.1);
    --accent-red: #ff4444;
    --accent-green: #10b981;

    --gradient-primary: linear-gradient(135deg, #00d4ff 0%, #7c3aed 100%);
    --gradient-primary-soft: linear-gradient(135deg, rgba(0, 212, 255, 0.1) 0%, rgba(124, 58, 237, 0.1) 100%);
    --gradient-gold: linear-gradient(135deg, #ffd700 0%, #ff8c00 100%);

    --border-color: rgba(255, 255, 255, 0.06);
    --border-highlight: rgba(0, 212, 255, 0.2);

    --glass-bg: rgba(15, 15, 45, 0.6);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

    /* Sizing */
    --container-max: 1200px;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    /* Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-spring: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* --- Particle Canvas --- */
#particleCanvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
    opacity: 0.4;
}

/* --- Container --- */
.amp-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Navigation --- */
#navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: var(--transition-smooth);
    backdrop-filter: blur(0px);
    background: transparent;
}

#navbar.scrolled {
    padding: 10px 0;
    background: rgba(5, 5, 16, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--text-primary);
    font-size: 1.2rem;
    font-weight: 700;
    letter-spacing: 0;
}

.logo-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary-soft);
    border: 1px solid var(--border-highlight);
    border-radius: var(--radius-sm);
}

.logo-highlight {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 8px;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.nav-link:hover {
    color: var(--accent-blue);
    background: var(--accent-blue-dim);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition-fast);
}

/* --- Hero Section --- */
.hero {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px 24px 80px;
    max-width: var(--container-max);
    margin: 0 auto;
    gap: 60px;
}

.hero-content {
    flex: 1;
    max-width: 600px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-blue);
    background: var(--accent-blue-dim);
    border: 1px solid rgba(0, 212, 255, 0.2);
    border-radius: 50px;
    padding: 8px 20px;
    margin-bottom: 28px;
    animation: fadeInUp 0.8s ease forwards;
}

.badge-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent-blue);
    animation: pulse 2s ease infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(0.8); }
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: 0;
    margin-bottom: 20px;
    animation: fadeInUp 0.8s ease 0.1s forwards;
    opacity: 0;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 36px;
    animation: fadeInUp 0.8s ease 0.2s forwards;
    opacity: 0;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 50px;
    animation: fadeInUp 0.8s ease 0.3s forwards;
    opacity: 0;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: inherit;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition-smooth);
    border: none;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #fff;
    box-shadow: 0 4px 24px rgba(0, 212, 255, 0.3), 0 0 0 0 rgba(0, 212, 255, 0);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(0, 212, 255, 0.4), 0 0 60px rgba(0, 212, 255, 0.1);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    background: var(--accent-blue-dim);
    transform: translateY(-2px);
}

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

.btn-ghost:hover {
    color: var(--text-primary);
    border-color: var(--text-muted);
    background: rgba(255, 255, 255, 0.03);
}

/* --- Hero Stats --- */
.hero-stats {
    display: flex;
    align-items: center;
    gap: 24px;
    animation: fadeInUp 0.8s ease 0.4s forwards;
    opacity: 0;
}

.stat {
    text-align: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-family: 'JetBrains Mono', monospace;
}

.stat-suffix {
    font-size: 1.2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-family: 'JetBrains Mono', monospace;
}

.stat-label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-top: 4px;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--border-color);
}

/* --- Hero Visual (Ammeter) --- */
.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    animation: fadeIn 1.2s ease 0.5s forwards;
    opacity: 0;
}

.hero-glow {
    position: absolute;
    width: 400px;
    height: 400px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(0, 212, 255, 0.15) 0%, transparent 70%);
    filter: blur(40px);
    animation: glowPulse 4s ease infinite;
}

@keyframes glowPulse {
    0%, 100% { transform: scale(1); opacity: 0.6; }
    50% { transform: scale(1.1); opacity: 1; }
}

.ammeter-display {
    position: relative;
    z-index: 2;
}

.ammeter-svg {
    width: 360px;
    height: 240px;
    filter: drop-shadow(0 0 40px rgba(0, 212, 255, 0.1));
}

.needle-animate {
    transform-origin: 150px 120px;
    animation: needleSwing 3s ease infinite;
}

@keyframes needleSwing {
    0% { transform: rotate(-40deg); }
    50% { transform: rotate(20deg); }
    100% { transform: rotate(-40deg); }
}

/* --- Sections --- */
.amp-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.amp-section-header,
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.amp-section-tag,
.section-tag {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: none;
    letter-spacing: 0;
    color: var(--accent-blue);
    background: var(--accent-blue-dim);
    border: 1px solid rgba(0, 212, 255, 0.15);
    padding: 6px 16px;
    border-radius: 50px;
    margin-bottom: 16px;
}

.amp-section-title,
.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    letter-spacing: 0;
    margin-bottom: 16px;
}

.amp-section-desc,
.section-desc {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ===================================
   CALCULATOR SECTION
   =================================== */
.first-section {
    padding-top: 88px;
}

.calculator-section {
    background: radial-gradient(ellipse at center top, rgba(0, 212, 255, 0.03) 0%, transparent 60%);
}

/* Tabs */
.calc-tabs {
    display: flex;
    gap: 12px;
    margin-bottom: 32px;
    overflow-x: auto;
    padding-bottom: 4px;
}

.calc-tab {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 24px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-smooth);
    font-family: inherit;
    color: var(--text-secondary);
    flex: 1;
    min-width: 200px;
}

.calc-tab:hover {
    border-color: var(--border-highlight);
    color: var(--text-primary);
    background: var(--bg-card-hover);
}

.calc-tab.active {
    border-color: var(--accent-blue);
    color: var(--text-primary);
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.08) 0%, rgba(124, 58, 237, 0.05) 100%);
    box-shadow: 0 0 30px rgba(0, 212, 255, 0.1);
}

.tab-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 212, 255, 0.05);
    border-radius: var(--radius-sm);
    flex-shrink: 0;
    transition: var(--transition-fast);
}

.calc-tab.active .tab-icon {
    background: var(--accent-blue-dim);
    color: var(--accent-blue);
}

.tab-text {
    display: flex;
    flex-direction: column;
    text-align: left;
}

.tab-title {
    font-size: 0.9rem;
    font-weight: 600;
}

.tab-formula {
    font-size: 0.8rem;
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-muted);
    margin-top: 2px;
}

.calc-tab.active .tab-formula {
    color: var(--accent-blue);
}

/* Calculator Card */
.calculator-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    box-shadow: var(--glass-shadow), 0 0 60px rgba(0, 212, 255, 0.03);
    overflow: hidden;
}

.calc-body {
    padding: 48px;
}

.dedicated-calculator .calc-body {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.dedicated-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
}

.dedicated-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 14px;
    border-radius: 999px;
    background: rgba(0, 212, 255, 0.12);
    border: 1px solid rgba(0, 212, 255, 0.35);
    color: var(--accent-blue);
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0;
    text-transform: none;
}

.dedicated-formula {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-secondary);
    font-size: 0.82rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
}

.dedicated-grid.calc-mode.active {
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.dedicated-select {
    height: 56px;
    line-height: 1.2;
    padding: 0 44px 0 20px;
    font-size: 1rem;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image:
        linear-gradient(45deg, transparent 50%, var(--accent-blue) 50%),
        linear-gradient(135deg, var(--accent-blue) 50%, transparent 50%);
    background-position:
        calc(100% - 16px) calc(50% - 3px),
        calc(100% - 10px) calc(50% - 3px);
    background-size: 6px 6px, 6px 6px;
    background-repeat: no-repeat;
}

.dedicated-select option {
    color: #111827;
    background: #ffffff;
    line-height: 1.35;
}

.is-readonly {
    border-color: rgba(0, 212, 255, 0.28);
    background: rgba(0, 212, 255, 0.08);
    color: var(--accent-blue);
}

.dedicated-helper {
    margin-top: -6px;
    color: var(--text-secondary);
    font-size: 0.88rem;
    line-height: 1.6;
}

/* Calculator Modes */
.calc-mode {
    display: none;
    gap: 24px;
}

.calc-mode.active {
    display: grid;
    grid-template-columns: 1fr 1fr;
    animation: fadeIn 0.4s ease;
}

/* Input Groups */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.input-label svg {
    color: var(--accent-blue);
    opacity: 0.7;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.calc-input {
    width: 100%;
    padding: 16px 60px 16px 20px;
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-input);
    color: var(--text-primary);
    font-size: 1.1rem;
    font-family: 'JetBrains Mono', monospace;
    font-weight: 500;
    transition: var(--transition-fast);
    outline: none;
}

.calc-input::placeholder {
    color: var(--text-muted);
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 0.95rem;
}

.calc-input:focus {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 4px var(--accent-blue-dim), 0 0 20px rgba(0, 212, 255, 0.08);
}

.input-unit {
    position: absolute;
    right: 16px;
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--accent-blue);
    font-family: 'JetBrains Mono', monospace;
    pointer-events: none;
}

.input-hint {
    font-size: 0.78rem;
    color: var(--text-muted);
}




/* Result */
.calc-result {
    margin-top: 40px;
    padding: 32px;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.06) 0%, rgba(124, 58, 237, 0.04) 100%);
    border: 1px solid rgba(0, 212, 255, 0.15);
    border-radius: var(--radius-lg);
    animation: resultSlideIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.calc-result.hidden {
    display: none;
}

@keyframes resultSlideIn {
    from { opacity: 0; transform: translateY(20px) scale(0.98); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.result-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: none;
    letter-spacing: 0;
    color: var(--accent-green);
}

.result-icon {
    color: var(--accent-green);
}

.result-value-container {
    text-align: center;
    padding: 24px 0;
}

.result-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
    display: block;
}

.result-value {
    font-size: 3.5rem;
    font-weight: 900;
    font-family: 'JetBrains Mono', monospace;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: 0;
}

.result-unit {
    display: block;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 4px;
    font-weight: 500;
}

.result-breakdown {
    display: flex;
    gap: 16px;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.breakdown-item {
    flex: 1;
    text-align: center;
    padding: 16px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
}

.breakdown-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: none;
    letter-spacing: 0;
    display: block;
    margin-bottom: 6px;
}

.breakdown-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* ===================================
   CIRCUIT DIAGRAM SECTION
   =================================== */
.diagram-section {
    background: radial-gradient(ellipse at center, rgba(124, 58, 237, 0.03) 0%, transparent 60%);
}

.diagram-container {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    box-shadow: var(--glass-shadow);
    overflow: hidden;
}

.diagram-controls {
    display: flex;
    align-items: center;
    gap: 32px;
    padding: 28px 36px;
    border-bottom: 1px solid var(--border-color);
    background: rgba(0, 0, 0, 0.15);
    flex-wrap: wrap;
}

.diagram-control-group {
    flex: 1;
    min-width: 180px;
}

.diagram-label {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: none;
    letter-spacing: 0;
    color: var(--text-muted);
    margin-bottom: 10px;
    display: block;
}

.diagram-slider-wrap {
    display: flex;
    align-items: center;
    gap: 14px;
}

.diagram-slider {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    height: 6px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 3px;
    outline: none;
    cursor: pointer;
}

.diagram-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--gradient-primary);
    cursor: pointer;
    border: 3px solid var(--bg-primary);
    box-shadow: 0 0 12px rgba(0, 212, 255, 0.4);
    transition: var(--transition-fast);
}

.diagram-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 20px rgba(0, 212, 255, 0.6);
}

.diagram-slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--gradient-primary);
    cursor: pointer;
    border: 3px solid var(--bg-primary);
    box-shadow: 0 0 12px rgba(0, 212, 255, 0.4);
}

.diagram-value {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
    font-size: 1rem;
    color: var(--accent-blue);
    min-width: 60px;
    text-align: right;
}

.diagram-result-display {
    padding: 16px 28px;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.08), rgba(124, 58, 237, 0.05));
    border: 1px solid rgba(0, 212, 255, 0.15);
    border-radius: var(--radius-md);
    text-align: center;
    min-width: 160px;
}

.diagram-result-label {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: none;
    letter-spacing: 0;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.diagram-result-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.6rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.diagram-canvas-wrap {
    padding: 20px;
    display: flex;
    justify-content: center;
    overflow: hidden;
}

#circuitCanvas {
    width: 100%;
    max-width: 900px;
    height: auto;
    border-radius: var(--radius-md);
}

.diagram-legend {
    display: flex;
    justify-content: center;
    gap: 28px;
    padding: 20px 36px;
    border-top: 1px solid var(--border-color);
    background: rgba(0, 0, 0, 0.1);
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.legend-color {
    width: 12px;
    height: 12px;
    border-radius: 3px;
}

/* ===================================
   FORMULAS SECTION
   =================================== */
.formulas-section {
    background: radial-gradient(ellipse at center top, rgba(255, 215, 0, 0.02) 0%, transparent 60%);
}

.formulas-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.formula-card {
    position: relative;
    padding: 32px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: var(--transition-smooth);
    overflow: hidden;
}

.formula-card-glow {
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at center, rgba(0, 212, 255, 0.03) 0%, transparent 50%);
    opacity: 0;
    transition: var(--transition-smooth);
    pointer-events: none;
}

.formula-card:hover {
    border-color: var(--border-highlight);
    background: var(--bg-card-hover);
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.formula-card:hover .formula-card-glow {
    opacity: 1;
}

.formula-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-blue-dim);
    border: 1px solid rgba(0, 212, 255, 0.15);
    border-radius: var(--radius-md);
    color: var(--accent-blue);
    margin-bottom: 20px;
}

.formula-title {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 12px;
    letter-spacing: 0;
}

.formula-expression {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 16px;
}

.formula-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}

.formula-example {
    padding: 12px 16px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-family: 'JetBrains Mono', monospace;
}

.example-label {
    color: var(--accent-gold);
    font-weight: 600;
    margin-right: 8px;
    font-family: 'Inter', sans-serif;
}

.formula-example strong {
    color: var(--accent-blue);
}

/* Ohm's Triangle Card */
.formula-card-highlight {
    border-color: rgba(255, 215, 0, 0.15);
}

.formula-card-highlight .formula-icon {
    background: var(--accent-gold-dim);
    border-color: rgba(255, 215, 0, 0.2);
    color: var(--accent-gold);
}

.ohm-triangle {
    display: flex;
    justify-content: center;
    margin: 20px 0 24px;
}

.triangle-visual {
    width: 160px;
    text-align: center;
}

.triangle-top {
    font-family: 'JetBrains Mono', monospace;
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent-gold);
    padding-bottom: 10px;
}

.triangle-divider {
    height: 3px;
    background: var(--gradient-gold);
    border-radius: 2px;
    margin: 0 10px;
}

.triangle-bottom {
    display: flex;
    justify-content: center;
    gap: 16px;
    padding-top: 10px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--accent-blue);
}

.triangle-bottom span:nth-child(2) {
    color: var(--text-muted);
    font-size: 1.2rem;
}

/* ===================================
   GUIDE SECTION
   =================================== */
.guide-section {
    background: radial-gradient(ellipse at center, rgba(0, 212, 255, 0.02) 0%, transparent 60%);
}

.guide-steps {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.guide-step {
    display: flex;
    align-items: center;
    gap: 36px;
    padding: 40px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    transition: var(--transition-smooth);
}

.guide-step:hover {
    border-color: var(--border-highlight);
    background: var(--bg-card-hover);
    transform: translateX(4px);
}

.step-number {
    font-size: 4rem;
    font-weight: 900;
    font-family: 'JetBrains Mono', monospace;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    opacity: 0.3;
    flex-shrink: 0;
    line-height: 1;
}

.step-content {
    flex: 1;
}

.step-content h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: 0;
}

.step-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
}

.step-visual {
    flex-shrink: 0;
}

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

.step-icon-item {
    width: 64px;
    height: 64px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--accent-blue-dim);
    border: 1px solid rgba(0, 212, 255, 0.15);
    border-radius: var(--radius-sm);
    transition: var(--transition-spring);
}

.step-icon-item span {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 800;
    font-size: 1.2rem;
    color: var(--accent-blue);
}

.step-icon-item small {
    font-size: 0.6rem;
    color: var(--text-muted);
    margin-top: 2px;
}

.step-formula-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.sf-item {
    padding: 10px 16px;
    background: var(--accent-blue-dim);
    border: 1px solid rgba(0, 212, 255, 0.1);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.sf-item code {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--accent-blue);
}

.step-result-preview {
    width: 160px;
    padding: 20px;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.08), rgba(124, 58, 237, 0.05));
    border: 1px solid rgba(0, 212, 255, 0.15);
    border-radius: var(--radius-md);
    text-align: center;
}

.srp-label {
    font-size: 0.7rem;
    text-transform: none;
    letter-spacing: 0;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.srp-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.srp-value small {
    font-size: 1rem;
}

.srp-bar {
    height: 4px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 2px;
    margin-top: 12px;
    overflow: hidden;
}

.srp-bar-fill {
    height: 100%;
    width: 60%;
    background: var(--gradient-primary);
    border-radius: 2px;
    animation: barPulse 2s ease infinite;
}

@keyframes barPulse {
    0%, 100% { width: 40%; }
    50% { width: 80%; }
}

/* ===================================
   REFERENCE TABLE SECTION
   =================================== */
.reference-section {
    background: radial-gradient(ellipse at center bottom, rgba(124, 58, 237, 0.03) 0%, transparent 60%);
}

.reference-table-wrap {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    overflow: hidden;
    box-shadow: var(--glass-shadow);
}

.reference-table {
    width: 100%;
    border-collapse: collapse;
}

.reference-table thead {
    background: rgba(0, 0, 0, 0.2);
}

.reference-table th {
    padding: 18px 24px;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: none;
    letter-spacing: 0;
    color: var(--text-muted);
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.reference-table td {
    padding: 16px 24px;
    font-size: 0.95rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.03);
    transition: var(--transition-fast);
}

.reference-table tbody tr:hover td {
    background: rgba(0, 212, 255, 0.03);
}

.reference-table tbody tr:last-child td {
    border-bottom: none;
}

.device-icon {
    margin-right: 8px;
    font-size: 1.1rem;
}

.amp-badge {
    display: inline-flex;
    padding: 4px 12px;
    border-radius: 50px;
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
    font-size: 0.85rem;
}

.amp-low {
    background: rgba(16, 185, 129, 0.1);
    color: #10b981;
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.amp-medium {
    background: rgba(255, 215, 0, 0.1);
    color: #ffd700;
    border: 1px solid rgba(255, 215, 0, 0.2);
}

.amp-high {
    background: rgba(255, 140, 0, 0.1);
    color: #ff8c00;
    border: 1px solid rgba(255, 140, 0, 0.2);
}

.amp-danger {
    background: rgba(255, 68, 68, 0.1);
    color: #ff4444;
    border: 1px solid rgba(255, 68, 68, 0.2);
}

/* ===================================
   FAQ SECTION
   =================================== */
.faq-section {
    background: radial-gradient(ellipse at center, rgba(0, 212, 255, 0.02) 0%, transparent 60%);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition-smooth);
}

.faq-item:hover {
    border-color: var(--border-highlight);
}

.faq-item.active {
    border-color: var(--accent-blue);
    box-shadow: 0 0 30px rgba(0, 212, 255, 0.05);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    text-align: left;
    transition: var(--transition-fast);
}

.faq-question:hover {
    color: var(--accent-blue);
}

.faq-chevron {
    flex-shrink: 0;
    color: var(--text-muted);
    transition: var(--transition-smooth);
}

.faq-item.active .faq-chevron {
    transform: rotate(180deg);
    color: var(--accent-blue);
}

.faq-answer {
    max-height: 0;
    padding: 0 24px 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-item.active .faq-answer {
    max-height: 300px;
    padding: 0 24px 20px;
}

.faq-answer p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
}

/* ===================================
   FOOTER
   =================================== */
.footer {
    position: relative;
    z-index: 1;
    border-top: 1px solid var(--border-color);
    padding: 70px 0 30px;
    background: rgba(0, 0, 0, 0.3);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 50px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-tagline {
    font-size: 0.9rem;
    color: var(--text-muted);
    line-height: 1.8;
    max-width: 320px;
}

.footer-links-group h4 {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: none;
    letter-spacing: 0;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.footer-links-group a {
    display: block;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    padding: 5px 0;
    transition: var(--transition-fast);
}

.footer-links-group a:hover {
    color: var(--accent-blue);
    transform: translateX(4px);
}

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding-top: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.footer-bottom p {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.footer-disclaimer {
    font-style: italic;
    opacity: 0.7;
}

/* ===================================
   ANIMATIONS
   =================================== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* Scroll Reveal */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===================================
   RESPONSIVE DESIGN
   =================================== */
@media (max-width: 1024px) {
    .hero {
        flex-direction: column;
        text-align: center;
        padding: 120px 24px 60px;
        gap: 40px;
    }

    .hero-content {
        max-width: 100%;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .calc-mode.active {
        grid-template-columns: 1fr;
    }

    .guide-step {
        flex-direction: column;
        text-align: center;
        gap: 20px;
        padding: 28px;
    }

    .step-number {
        font-size: 2.5rem;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 30px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(5, 5, 16, 0.95);
        backdrop-filter: blur(20px);
        border-bottom: 1px solid var(--border-color);
        flex-direction: column;
        padding: 16px;
    }

    .nav-links.open {
        display: flex;
    }

    .nav-toggle {
        display: flex;
    }

    .calc-tabs {
        flex-direction: column;
    }

    .calc-tab {
        min-width: auto;
    }

    .calc-body {
        padding: 28px 20px;
    }

    .dedicated-header {
        align-items: flex-start;
        flex-direction: column;
    }

    .dedicated-formula {
        width: 100%;
        overflow-x: auto;
    }

    .calc-actions {
        flex-direction: column;
    }

    .diagram-controls {
        flex-direction: column;
        gap: 16px;
        padding: 20px;
    }

    .diagram-legend {
        flex-direction: column;
        align-items: center;
        gap: 12px;
    }

    .formulas-grid {
        grid-template-columns: 1fr;
    }

    .result-breakdown {
        flex-direction: column;
    }

    .reference-table-wrap {
        overflow-x: auto;
    }

    .reference-table {
        min-width: 600px;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .hero-title {
        font-size: 2.2rem;
    }

    .ammeter-svg {
        width: 280px;
        height: 190px;
    }
}

@media (max-width: 480px) {
    .hero-stats {
        flex-direction: column;
        gap: 16px;
    }

    .stat-divider {
        width: 40px;
        height: 1px;
    }

    .hero-actions {
        flex-direction: column;
    }

    .hero-badge {
        font-size: 0.75rem;
    }
}

/* --- Number Input Arrow Styling --- */
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    opacity: 0.5;
}

/* --- Selection Color --- */
::selection {
    background: rgba(0, 212, 255, 0.3);
    color: #fff;
}

/* --- Scrollbar Styling --- */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}