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

:root {
    --primary: #FF5733;
    --secondary: #C70039;
    --success: #2ECC71;
    --danger: #E74C3C;
    --warning: #F39C12;
    --bg-dark: #0F0F0F;
    --bg-card: #1E1E1E;
    --bg-elevated: #2A2A2A;
    --text-primary: #FFFFFF;
    --text-secondary: #AAAAAA;
    --border: rgba(255, 255, 255, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-dark) 0%, #1A1A1A 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Navigation */
.navbar {
    background: rgba(30, 30, 30, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-btn {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1rem;
}

.nav-btn:hover {
    background: var(--bg-elevated);
    border-color: var(--primary);
}

/* Navigation Actions Container */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Portfolio Home Button */
.portfolio-home-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: linear-gradient(135deg, rgba(255, 87, 51, 0.1), rgba(199, 0, 57, 0.1));
    border: 1px solid var(--primary);
    border-radius: 8px;
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    transition: all 0.3s;
}

.portfolio-home-btn:hover {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--bg-primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 87, 51, 0.4);
}

.portfolio-home-btn .home-icon {
    font-size: 1.2rem;
}

.portfolio-home-btn .home-text {
    display: inline;
}

/* Main Container */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    flex: 1;
    width: 100%;
}

/* Screen Management */
.screen {
    display: none;
}

.screen.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

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

/* Hero Section */
.hero-section {
    text-align: center;
    padding: 3rem 2rem;
    background: linear-gradient(135deg, rgba(255, 87, 51, 0.1) 0%, rgba(199, 0, 57, 0.1) 100%);
    border-radius: 16px;
    margin-bottom: 2rem;
    border: 1px solid rgba(255, 87, 51, 0.2);
}

.hero-section h2 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
}

.stats-card {
    display: inline-block;
    background: var(--bg-card);
    padding: 1.5rem 3rem;
    border-radius: 12px;
    border: 1px solid var(--border);
}

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

.stat-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 900;
    color: var(--primary);
}

/* Workout Categories */
.workout-category {
    margin-bottom: 3rem;
}

.workout-category h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    padding-left: 0.5rem;
}

.workout-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.workout-card {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--border);
    transition: all 0.3s;
    cursor: pointer;
}

.workout-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: 0 8px 24px rgba(255, 87, 51, 0.2);
}

.workout-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.workout-card h4 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.workout-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    min-height: 2.5rem;
}

/* Buttons */
.btn-primary,
.btn-secondary,
.btn-start,
.btn-danger,
.btn-control {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    width: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
}

.btn-primary:hover {
    transform: scale(1.02);
    box-shadow: 0 4px 12px rgba(255, 87, 51, 0.4);
}

.btn-start {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
}

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

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

.btn-control {
    background: var(--bg-elevated);
    color: var(--text-primary);
    border: 1px solid var(--border);
    font-size: 1.2rem;
}

/* Config Screen */
.config-container {
    max-width: 600px;
    margin: 0 auto;
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--border);
}

.config-container h2 {
    margin-bottom: 2rem;
    text-align: center;
}

#configOptions {
    margin-bottom: 2rem;
}

.config-option {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    background: var(--bg-elevated);
    border-radius: 12px;
    margin-bottom: 1rem;
}

.config-option label {
    font-size: 1.1rem;
}

.config-option input,
.config-option select {
    background: var(--bg-dark);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 1rem;
    width: 100px;
    text-align: center;
}

.config-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

/* Workout Running Screen */
.workout-container {
    max-width: 800px;
    margin: 0 auto;
}

.workout-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.workout-header h2 {
    font-size: 2rem;
}

.workout-header p {
    color: var(--text-secondary);
}

.workout-display {
    background: var(--bg-card);
    padding: 3rem;
    border-radius: 16px;
    text-align: center;
    margin-bottom: 2rem;
    border: 2px solid var(--primary);
}

.workout-metric {
    margin-bottom: 2rem;
}

.metric-label {
    display: block;
    color: var(--text-secondary);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.metric-value {
    font-size: 4rem;
    font-weight: 900;
    color: var(--primary);
}

.workout-status {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.progress-bar-container {
    width: 100%;
    height: 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
    transition: width 0.3s ease;
    border-radius: 10px;
}

.workout-controls {
    display: flex;
    justify-content: center;
}

.workout-controls button {
    min-width: 200px;
}

/* Rest Screen */
.rest-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
    background: var(--bg-card);
    padding: 3rem;
    border-radius: 16px;
    border: 2px solid var(--warning);
}

.rest-timer {
    font-size: 5rem;
    font-weight: 900;
    color: var(--warning);
    margin: 2rem 0;
}

#restMessage {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Complete Screen */
.complete-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
    background: var(--bg-card);
    padding: 3rem;
    border-radius: 16px;
    border: 2px solid var(--success);
}

.complete-icon {
    font-size: 5rem;
    margin-bottom: 1rem;
}

.complete-stats {
    background: var(--bg-elevated);
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
}

.complete-stats p {
    font-size: 1.2rem;
    margin: 0.5rem 0;
}

/* History */
.history-card {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--border);
}

.history-item {
    display: flex;
    justify-content: space-between;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
}

.history-item:last-child {
    border-bottom: none;
}

.history-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

/* Settings Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 16px;
    max-width: 500px;
    width: 90%;
    border: 1px solid var(--border);
}

.modal-content h2 {
    margin-bottom: 2rem;
}

.setting-item {
    margin-bottom: 1.5rem;
}

.setting-item label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.setting-item input,
.setting-item select {
    width: 100%;
    padding: 0.75rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    color: var(--text-primary);
    border-radius: 8px;
    font-size: 1rem;
}

.modal-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-top: 2rem;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-section h2 {
        font-size: 2rem;
    }
    
    .metric-value {
        font-size: 3rem;
    }
    
    .rest-timer {
        font-size: 3.5rem;
    }
    
    .workout-grid {
        grid-template-columns: 1fr;
    }
    
    .portfolio-home-btn .home-text {
        display: none;
    }
    
    .portfolio-home-btn {
        padding: 0.5rem;
    }
    
    .nav-actions {
        gap: 0.5rem;
    }
}