:root {
    /* Light Theme */
    --light-bg: #f5f7fa;
    --light-bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --light-container-bg: #ffffff;
    --light-text: #333333;
    --light-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --light-primary: #4a6fa5;
    --light-secondary: #ff7e5f;
    --light-tertiary: #6b8e23;
    --light-work: #ff6b6b;
    --light-break: #4ecdc4;
    
    /* Dark Theme */
    --dark-bg: #1a1a2e;
    --dark-bg-gradient: linear-gradient(135deg, #16213e 0%, #0f3460 100%);
    --dark-container-bg: #1f1f3d;
    --dark-text: #e6e6e6;
    --dark-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    --dark-primary: #6a8fc7;
    --dark-secondary: #ff9a76;
    --dark-tertiary: #8fbc8f;
    --dark-work: #ff7676;
    --dark-break: #76e8e0;
    
    /* Current Theme - Default to Dark */
    --bg: var(--dark-bg);
    --bg-gradient: var(--dark-bg-gradient);
    --container-bg: var(--dark-container-bg);
    --text: var(--dark-text);
    --shadow: var(--dark-shadow);
    --primary: var(--dark-primary);
    --secondary: var(--dark-secondary);
    --tertiary: var(--dark-tertiary);
    --work: var(--dark-work);
    --break: var(--dark-break);
    
    --transition: all 0.3s ease;
    --border-radius: 15px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--bg-gradient);
    color: var(--text);
    transition: var(--transition);
}

.container {
    width: 100%;
    max-width: 500px;
    background: var(--container-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
    position: relative;
}

.header {
    margin-bottom: 1.5rem;
}

.header h1 {
    color: var(--primary);
    margin-bottom: 0.5rem;
    font-size: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.neon-text {
    color: var(--primary);
    text-shadow: 0 0 5px rgba(106, 143, 199, 0.5),
                 0 0 10px rgba(106, 143, 199, 0.3),
                 0 0 15px rgba(106, 143, 199, 0.2);
}

.session-indicator {
    margin-top: 1rem;
}

#session-type {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
    display: block;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    overflow: hidden;
    margin-top: 0.5rem;
}

.progress-fill {
    height: 100%;
    width: 100%;
    transition: width 0.5s linear;
}

.timer-display {
    font-size: 5rem;
    font-weight: bold;
    font-family: 'Courier New', monospace;
    margin: 1.5rem 0;
    color: var(--text);
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.1);
    letter-spacing: 2px;
}

.controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
}

.btn {
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.btn-primary {
    background-color: var(--primary);
    color: white;
}

.btn-secondary {
    background-color: var(--secondary);
    color: white;
}

.btn-tertiary {
    background-color: var(--tertiary);
    color: white;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.2);
    filter: brightness(1.1);
}

.btn:active {
    transform: translateY(1px);
}

.settings {
    background-color: rgba(255, 255, 255, 0.1);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-top: 1.5rem;
}

.setting {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.setting:last-child {
    margin-bottom: 0;
}

.setting label {
    font-weight: 500;
    color: var(--text);
}

.setting input {
    width: 70px;
    padding: 0.5rem;
    background-color: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 5px;
    text-align: center;
    font-size: 1rem;
    color: var(--text);
    transition: var(--transition);
}

.setting input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(106, 143, 199, 0.3);
}

.social-icons {
    display: flex;
    justify-content: center;
    gap: 1.2rem;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.social-icon {
    color: var(--text);
    font-size: 1.2rem;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    background-color: rgba(255, 255, 255, 0.1);
}

.social-icon:hover {
    background-color: var(--primary);
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

.notification {
    position: fixed;
    bottom: -100px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary);
    color: white;
    padding: 1rem 2rem;
    border-radius: 50px;
    box-shadow: var(--shadow);
    opacity: 0;
    transition: all 0.5s ease;
    z-index: 100;
}

.notification.show {
    bottom: 30px;
    opacity: 1;
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
}

#theme-switcher {
    background: rgba(255, 255, 255, 0.1);
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text);
    font-size: 1.2rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

#theme-switcher:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: rotate(30deg);
}

#theme-switcher .fa-moon,
#theme-switcher .fa-sun {
    position: absolute;
    transition: var(--transition);
}

#theme-switcher .fa-moon {
    opacity: 1;
}

#theme-switcher .fa-sun {
    opacity: 0;
}

[data-theme="light"] #theme-switcher .fa-moon {
    opacity: 0;
}

[data-theme="light"] #theme-switcher .fa-sun {
    opacity: 1;
}

/* Animation for session switch */
@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.session-switch {
    animation: pulse 0.5s ease;
}

/* Responsive design */
@media (max-width: 600px) {
    .container {
        padding: 1.5rem;
        margin: 1rem;
    }
    
    .timer-display {
        font-size: 3.5rem;
    }
    
    .controls {
        flex-direction: column;
        gap: 0.8rem;
    }
    
    .btn {
        justify-content: center;
    }
    
    .social-icons {
        gap: 1rem;
    }
}

/* Theme Switching */
[data-theme="light"] {
    --bg: var(--light-bg);
    --bg-gradient: var(--light-bg-gradient);
    --container-bg: var(--light-container-bg);
    --text: var(--light-text);
    --shadow: var(--light-shadow);
    --primary: var(--light-primary);
    --secondary: var(--light-secondary);
    --tertiary: var(--light-tertiary);
    --work: var(--light-work);
    --break: var(--light-break);
}

[data-theme="dark"] {
    --bg: var(--dark-bg);
    --bg-gradient: var(--dark-bg-gradient);
    --container-bg: var(--dark-container-bg);
    --text: var(--dark-text);
    --shadow: var(--dark-shadow);
    --primary: var(--dark-primary);
    --secondary: var(--dark-secondary);
    --tertiary: var(--dark-tertiary);
    --work: var(--dark-work);
    --break: var(--dark-break);
}