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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --shadow: rgba(0, 0, 0, 0.3);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--background) 0%, #1e293b 100%);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 40px;
    animation: fadeInDown 0.6s ease-out;
    position: relative;
}

header h1 {
    font-size: 3em;
    margin-bottom: 10px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1em;
}

.btn-toggle {
    position: absolute;
    top: 0;
    right: 0;
    padding: 10px 20px;
    font-size: 0.9em;
    font-weight: 600;
    border: 2px solid var(--surface-light);
    border-radius: 8px;
    background: var(--surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-toggle:hover {
    border-color: var(--primary-color);
    background: var(--surface-light);
    transform: translateY(-2px);
}

.btn-toggle.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-color: transparent;
    color: white;
}

.timer-display {
    background: var(--surface);
    border-radius: 20px;
    padding: 40px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px var(--shadow);
    animation: fadeIn 0.8s ease-out;
}

.timer-name {
    font-size: 1.8em;
    font-weight: bold;
    text-align: center;
    margin-bottom: 30px;
    color: var(--primary-color);
    text-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
}

.countdown-wrapper {
    overflow-x: auto;
    margin-bottom: 20px;
}

.countdown {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    min-width: max-content;
}

.time-unit {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--surface-light);
    border-radius: 12px;
    padding: 20px;
    min-width: 100px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    transition: transform 0.2s ease;
}

.time-unit:hover {
    transform: translateY(-5px);
}

.time-unit.milliseconds {
    min-width: 120px;
}

.time-unit .value {
    font-size: 3em;
    font-weight: bold;
    color: var(--text-primary);
    line-height: 1;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.time-unit .label {
    font-size: 0.9em;
    color: var(--text-secondary);
    margin-top: 8px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.separator {
    font-size: 2.5em;
    font-weight: bold;
    color: var(--primary-color);
    margin: 0 5px;
}

.timer-status {
    text-align: center;
    font-size: 1.2em;
    color: var(--text-secondary);
    min-height: 30px;
}

.timer-status.expired {
    color: var(--danger);
    font-weight: bold;
    animation: pulse 1s infinite;
}

.controls {
    background: var(--surface);
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px var(--shadow);
    animation: fadeIn 1s ease-out;
}

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

.input-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-weight: 500;
}

.input-group input {
    width: 100%;
    padding: 12px 16px;
    font-size: 1em;
    border: 2px solid var(--surface-light);
    border-radius: 10px;
    background: var(--background);
    color: var(--text-primary);
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.btn {
    padding: 12px 24px;
    font-size: 1em;
    font-weight: 600;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-right: 10px;
    margin-bottom: 10px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

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

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
}

.btn-secondary {
    background: var(--surface-light);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: var(--primary-dark);
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.9em;
}

.share-section {
    background: var(--surface);
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px var(--shadow);
    animation: fadeIn 1.2s ease-out;
}

.share-section h2 {
    margin-bottom: 20px;
    font-size: 1.5em;
}

.share-url {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.share-url input {
    flex: 1;
    padding: 12px 16px;
    font-size: 0.95em;
    border: 2px solid var(--surface-light);
    border-radius: 10px;
    background: var(--background);
    color: var(--text-primary);
}

.share-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
}

.icon {
    margin-right: 5px;
}

#qrCodeSection {
    text-align: center;
    margin-top: 20px;
}

#qrCodeImage {
    max-width: 300px;
    border-radius: 10px;
    margin-bottom: 15px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

footer {
    text-align: center;
    color: var(--text-secondary);
    padding: 20px;
    font-size: 0.9em;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    header {
        position: static;
    }

    header h1 {
        font-size: 2em;
    }

    .btn-toggle {
        position: static;
        margin: 15px auto 0;
        font-size: 0.85em;
        padding: 8px 16px;
    }

    .timer-display {
        padding: 25px 15px;
    }

    .time-unit {
        min-width: 70px;
        padding: 15px 10px;
    }

    .time-unit .value {
        font-size: 2em;
    }

    .time-unit.milliseconds {
        min-width: 90px;
    }

    .separator {
        font-size: 2em;
    }

    .controls, .share-section {
        padding: 20px;
    }

    .btn {
        width: 100%;
        margin-right: 0;
    }

    .share-url {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .countdown {
        gap: 5px;
    }

    .time-unit {
        min-width: 60px;
        padding: 10px 5px;
    }

    .time-unit .value {
        font-size: 1.5em;
    }

    .time-unit.milliseconds {
        min-width: 75px;
    }

    .separator {
        font-size: 1.5em;
        margin: 0 2px;
    }
}