/* Reset basic styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Poppins', sans-serif;
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--bg-gradient);
    color: var(--fg);
    transition: background 0.5s ease, color 0.3s ease;
    position: relative;
    overflow: hidden;
}

/* Light mode (default) */
:root {
    --fg: #2c3e50;
    --accent: #ffffff;
    
    /* Focus session - blue gradient */
    --focus-light: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --focus-dark: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    
    /* Break session - green gradient */
    --break-light: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --break-dark: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    
    /* Long break - orange gradient */
    --longbreak-light: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
    --longbreak-dark: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}

body.light {
    --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

body.dark {
    --bg-gradient: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);
    --fg: #e0e0e0;
}

/* Dynamic backgrounds based on session type */
body.focus-session {
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

body.break-session {
    --bg-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

body.longbreak-session {
    --bg-gradient: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}

.container {
    max-width: 500px;
    width: 100%;
    padding: 2rem;
    text-align: center;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
    color: var(--accent);
}

header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.mode-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    width: 45px;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--accent);
}

.mode-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: rotate(20deg);
}

main {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.timer-container {
    display: flex;
    justify-content: center;
    margin: 1rem 0;
}

.circular-progress {
    position: relative;
    width: 280px;
    height: 280px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.circular-progress svg {
    position: absolute;
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.progress-bg {
    fill: none;
    stroke: rgba(255, 255, 255, 0.2);
    stroke-width: 8;
}

.progress-fill {
    fill: none;
    stroke: rgba(255, 255, 255, 0.9);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 565;
    stroke-dashoffset: 565;
    transition: stroke-dashoffset 0.5s linear;
}

.timer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.session-label {
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 1px;
    color: rgba(255, 255, 255, 0.8);
    text-transform: uppercase;
}

.timer-display {
    font-size: 5rem;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
    letter-spacing: -2px;
}

.session-subtitle {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 400;
}

.controls {
    display: flex;
    gap: 0.8rem;
    flex-wrap: wrap;
    justify-content: center;
    margin: 1rem 0;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Poppins', sans-serif;
    text-transform: uppercase;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.btn-primary {
    background: var(--accent);
    color: #667eea;
    flex: 1;
    min-width: 150px;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: var(--accent);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

.btn-secondary:active:not(:disabled) {
    transform: translateY(0);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.stats-container {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 12px;
    padding: 1.5rem;
    margin-top: 1rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.stat-label {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent);
}

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

.timer-container {
    animation: fadeIn 0.6s ease-out;
}

/* Responsive design */
@media (max-width: 600px) {
    .container {
        padding: 1.5rem;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .mode-btn {
        width: 40px;
        height: 40px;
    }

    .timer-display {
        font-size: 3.5rem;
    }

    .circular-progress {
        width: 220px;
        height: 220px;
    }

    .progress-bg,
    .progress-fill {
        stroke-width: 6;
    }

    .session-label {
        font-size: 0.8rem;
    }

    .session-subtitle {
        font-size: 0.75rem;
    }

    .controls {
        gap: 0.6rem;
    }

    .btn {
        padding: 10px 18px;
        font-size: 0.8rem;
    }

    .btn-primary {
        min-width: 120px;
    }

    .stat-value {
        font-size: 2rem;
    }
}

@media (max-width: 400px) {
    .container {
        padding: 1rem;
    }

    header {
        margin-bottom: 1.5rem;
    }

    header h1 {
        font-size: 1.3rem;
    }

    .timer-display {
        font-size: 2.8rem;
    }

    .circular-progress {
        width: 180px;
        height: 180px;
    }

    .controls {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}