:root {
    --bg-color: #0f1115;
    --card-bg: #181b21;
    --card-hover: #1f232b;
    --text-primary: #ffffff;
    --text-secondary: #a0a6b1;
    --accent-color: #00e5ff;
    /* Electric Blue */
    --accent-glow: rgba(0, 229, 255, 0.3);
    --success-color: #00ff9d;
    --border-color: #2a2f3a;
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-family);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.app-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.app-header {
    margin-bottom: 40px;
    text-align: center;
}

h1 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #fff 0%, #a0a6b1 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.02em;
}

/* Phase Selector */
.phase-selector {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    margin-bottom: 24px;
    background: var(--card-bg);
    padding: 16px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.phase-info {
    text-align: center;
    min-width: 200px;
}

.phase-info h2 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--accent-color);
    margin-bottom: 4px;
}

.phase-info span {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.nav-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-btn:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

/* Week Selector */
.week-selector {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

.week-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    cursor: pointer;
    transition: var(--transition);
}

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

.week-btn.active {
    background: var(--accent-color);
    color: #000;
    border-color: var(--accent-color);
    font-weight: 600;
    box-shadow: 0 0 15px var(--accent-glow);
}

/* Workout View */
.workout-view {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.day-card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 24px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.day-card:hover {
    border-color: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
}

.day-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.day-title h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.day-meta {
    font-size: 0.875rem;
    color: var(--text-secondary);
    display: flex;
    gap: 12px;
}

.day-tag {
    background: rgba(255, 255, 255, 0.05);
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 500;
}

.day-tag.strength {
    color: #ff7b7b;
    background: rgba(255, 123, 123, 0.1);
}

.day-tag.cardio {
    color: #7bafff;
    background: rgba(123, 175, 255, 0.1);
}

.day-tag.rest {
    color: #a0a6b1;
    background: rgba(160, 166, 177, 0.1);
}

.day-tag.optional {
    color: #ffd166;
    background: rgba(255, 209, 102, 0.1);
}

/* Exercise List */
.exercise-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.exercise-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 12px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 12px;
    transition: var(--transition);
    cursor: pointer;
}

.exercise-item:hover {
    background: rgba(255, 255, 255, 0.03);
}

.exercise-item.completed {
    opacity: 0.5;
}

.checkbox {
    width: 24px;
    height: 24px;
    border-radius: 6px;
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    flex-shrink: 0;
}

.exercise-item.completed .checkbox {
    background: var(--success-color);
    border-color: var(--success-color);
}

.checkbox svg {
    width: 16px;
    height: 16px;
    color: #000;
    opacity: 0;
    transform: scale(0.5);
    transition: var(--transition);
}

.exercise-item.completed .checkbox svg {
    opacity: 1;
    transform: scale(1);
}

.exercise-details {
    flex: 1;
}

.exercise-name {
    font-weight: 500;
    margin-bottom: 2px;
    color: var(--text-primary);
}

.exercise-meta {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.exercise-item.completed .exercise-name {
    text-decoration: line-through;
}

/* Weight Input */
.weight-input-container {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: 12px;
}

.weight-input {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border-color);
    color: var(--accent-color);
    border-radius: 6px;
    padding: 6px 10px;
    width: 80px;
    font-family: var(--font-family);
    font-size: 0.85rem;
    text-align: center;
    transition: var(--transition);
}

.weight-input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 10px var(--accent-glow);
}

.weight-input::placeholder {
    color: var(--text-secondary);
    opacity: 0.5;
}

/* Footer */
.app-footer {
    margin-top: 60px;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
    padding-bottom: 20px;
}

.text-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    text-decoration: underline;
    cursor: pointer;
    font-size: 0.75rem;
    margin-top: 12px;
    opacity: 0.6;
    transition: var(--transition);
}

.text-btn:hover {
    opacity: 1;
    color: var(--text-primary);
}

/* Responsive */
@media (max-width: 600px) {
    .phase-selector {
        padding: 12px;
        gap: 10px;
    }

    .phase-info h2 {
        font-size: 1rem;
    }

    .day-header {
        flex-direction: column;
        gap: 8px;
    }
}
/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(5px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.modal-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.modal-content {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 32px;
    border-radius: 16px;
    max-width: 400px;
    width: 90%;
    text-align: center;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    transform: translateY(0);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.modal-overlay.hidden .modal-content {
    transform: translateY(20px);
}

.modal-content h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: 24px;
    font-size: 0.9rem;
}

.modal-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.modal-btn {
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 0.9rem;
}

.modal-btn.cancel {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}

.modal-btn.cancel:hover {
    background: rgba(255, 255, 255, 0.05);
}

.modal-btn.confirm {
    background: rgba(255, 59, 48, 0.1); /* Red tint */
    color: #ff3b30;
    border: 1px solid rgba(255, 59, 48, 0.2);
}

.modal-btn.confirm:hover {
    background: rgba(255, 59, 48, 0.2);
    transform: translateY(-1px);
}