:root {
    --bg-primary: #0a0e1a;
    --bg-secondary: #121829;
    --bg-glass: rgba(255, 255, 255, 0.04);
    --accent: #6366f1;
    --accent-glow: rgba(99, 102, 241, 0.45);
    --accent-2: #8b5cf6;
    --start-color: #10b981;
    --start-glow: rgba(16, 185, 129, 0.4);
    --reset-color: #ef4444;
    --lap-color: #f59e0b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border: rgba(255, 255, 255, 0.08);
    --radius: 18px;
    --shadow: 0 20px 60px -15px rgba(0, 0, 0, 0.6);
}

[data-theme="light"] {
    --bg-primary: #f1f5f9;
    --bg-secondary: #ffffff;
    --bg-glass: rgba(255, 255, 255, 0.7);
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --border: rgba(0, 0, 0, 0.08);
    --shadow: 0 20px 60px -15px rgba(99, 102, 241, 0.2);
}

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

body {
    min-height: 100vh;
    font-family: 'Space Grotesk', system-ui, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1.5rem 1rem;
    overflow-x: hidden;
    transition: background 0.4s ease, color 0.4s ease;
    position: relative;
}

#bgCanvas {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    opacity: 0.5;
    pointer-events: none;
}

.stopwatch-app {
    width: 100%;
    max-width: 480px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: calc(var(--radius) + 8px);
    padding: 2rem;
    box-shadow: var(--shadow);
    backdrop-filter: blur(20px);
    position: relative;
    z-index: 1;
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 20px var(--accent-glow);
}

.logo svg {
    width: 24px;
    height: 24px;
    color: white;
}

.title-block h1 {
    font-size: 1.3rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 0.7rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.theme-toggle {
    width: 52px;
    height: 28px;
    border-radius: 20px;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 6px;
    position: relative;
    transition: background 0.3s ease;
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.theme-toggle svg {
    width: 14px;
    height: 14px;
    color: var(--text-secondary);
}

.toggle-thumb {
    position: absolute;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--accent);
    top: 50%;
    left: 4px;
    transform: translateY(-50%);
    transition: left 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 0 12px var(--accent-glow);
}

[data-theme="light"] .toggle-thumb {
    left: 28px;
}

.stopwatch-display {
    margin-bottom: 2rem;
}

.display-ring {
    position: relative;
    width: 280px;
    height: 280px;
    margin: 0 auto;
}

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

.ring-bg, .ring-progress {
    transition: stroke-dashoffset 0.1s linear, stroke 0.3s ease;
}

.time-display {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    z-index: 1;
}

.time-main {
    font-family: 'JetBrains Mono', monospace;
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1;
    letter-spacing: 0.02em;
    background: linear-gradient(135deg, var(--text-primary), var(--accent-2));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    transition: transform 0.1s ease;
}

.time-main.running {
    animation: pulse 1s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.01); }
}

.time-labels {
    display: flex;
    gap: 1.5rem;
    margin-top: 0.75rem;
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
}

.controls-section {
    margin-bottom: 1.5rem;
}

.control-row {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

.primary-controls {
    margin-bottom: 1rem;
}

.primary-controls .btn {
    flex: 1;
    min-width: 0;
}

.btn {
    border: none;
    border-radius: var(--radius);
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: transform 0.15s ease, box-shadow 0.2s ease, opacity 0.2s ease;
    padding: 1rem;
    color: white;
}

.btn svg {
    width: 20px;
    height: 20px;
}

.btn:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
}

.btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

.btn-start {
    background: linear-gradient(135deg, var(--start-color), #059669);
    box-shadow: 0 8px 24px -8px var(--start-glow);
    position: relative;
    overflow: hidden;
}

.btn-start::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.btn-start.running::before {
    opacity: 1;
}

.btn-start.running .play-icon { display: none; }
.btn-start.running .pause-icon { display: block; }
.btn-start:not(.running) .pause-icon { display: none; }
.btn-start:not(.running) .play-icon { display: block; }

.btn-start:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px -8px var(--start-glow);
}

.btn-lap {
    background: linear-gradient(135deg, var(--lap-color), #d97706);
    box-shadow: 0 8px 24px -8px rgba(245, 158, 11, 0.4);
}

.btn-lap:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px -8px rgba(245, 158, 11, 0.4);
}

.btn-reset {
    background: var(--bg-glass);
    border: 1px solid var(--border);
    color: var(--text-primary);
}

.btn-reset:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px -8px var(--accent-glow);
    border-color: var(--accent);
}

.secondary-controls {
    justify-content: space-between;
}

.btn-preset {
    background: var(--bg-glass);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 0.75rem 1rem;
    font-size: 0.85rem;
    flex: 1;
}

.btn-preset:hover {
    border-color: var(--accent);
    color: var(--text-primary);
}

.preset-times {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.preset-btn {
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-weight: 600;
    font-size: 0.75rem;
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.preset-btn:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.laps-section {
    margin-bottom: 1.5rem;
    animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.laps-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.laps-title {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--text-secondary);
}

.btn-clear-laps {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 8px;
    transition: color 0.2s ease, background 0.2s ease;
    display: flex;
}

.btn-clear-laps svg {
    width: 16px;
    height: 16px;
}

.btn-clear-laps:hover {
    color: #f87171;
    background: rgba(239, 68, 68, 0.1);
}

.laps-list {
    max-height: 200px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    padding-right: 0.25rem;
}

.laps-list::-webkit-scrollbar {
    width: 4px;
}
.laps-list::-webkit-scrollbar-thumb {
    background: var(--accent);
    border-radius: 4px;
}

.lap-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.6rem 0.85rem;
    background: var(--bg-glass);
    border-radius: 10px;
    font-size: 0.85rem;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateX(-20px); }
    to { opacity: 1; transform: translateX(0); }
}

.lap-item.best {
    border-left: 3px solid var(--start-color);
}

.lap-item.worst {
    border-left: 3px solid var(--reset-color);
}

.lap-number {
    color: var(--text-secondary);
    font-weight: 600;
    min-width: 40px;
}

.lap-time {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 600;
    color: var(--text-primary);
}

.lap-diff {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    color: var(--text-secondary);
    min-width: 60px;
    text-align: right;
}

.lap-diff.positive { color: var(--reset-color); }
.lap-diff.negative { color: var(--start-color); }

.laps-summary {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.5rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.summary-stat {
    text-align: center;
    padding: 0.75rem;
    background: var(--bg-glass);
    border-radius: 12px;
}

.summary-label {
    display: block;
    font-size: 0.6rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.summary-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--accent);
}

.stats-section {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.stat-card {
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 0.85rem 0.4rem;
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

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

.stat-label {
    font-size: 0.55rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.app-footer {
    margin-top: 1rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.75rem;
}

@media (max-width: 420px) {
    .stopwatch-app { padding: 1.5rem; }
    .display-ring { width: 240px; height: 240px; }
    .time-main { font-size: 2.8rem; }
    .primary-controls { flex-direction: column; }
    .primary-controls .btn { width: 100%; }
    .secondary-controls { flex-direction: column; }
    .preset-times { justify-content: center; }
    .stats-section { grid-template-columns: repeat(2, 1fr); }
    .laps-summary { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    .time-main.running { animation: none; }
}