body {
    margin: 0;
    font-family: 'Segoe UI', Arial, sans-serif;
    background: linear-gradient(135deg, #f8fafc 0%, #e0e7ff 100%);
    min-height: 100vh;
}
.container {
    max-width: 900px;
    margin: 10px auto;
    padding: 24px;
    background: linear-gradient(120deg, #f1f5fe 0%, #b8c8ff 100%);
    border-radius: 18px;
    box-shadow: 0 8px 32px rgba(60, 72, 88, 0.12);
}
h1 {
    text-align: center;
    color: #3b3b3b;
    margin-bottom: 32px;
    font-size: 2.5rem;
}
.sessions-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(2, 1fr);
    gap: 32px;
}
.session-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(120deg, #6366f1 0%, #60a5fa 100%);
    color: #fff;
    border-radius: 14px;
    box-shadow: 0 4px 16px rgba(60, 72, 88, 0.10);
    text-decoration: none;
    padding: 32px 16px;
    transition: transform 0.18s, box-shadow 0.18s;
}
.session-card:hover {
    transform: translateY(-6px) scale(1.04);
    box-shadow: 0 8px 32px rgba(60, 72, 88, 0.18);
    background: linear-gradient(120deg, #818cf8 0%, #38bdf8 100%);
}
.session-card h2 {
    margin: 0 0 12px 0;
    font-size: 1.5rem;
    font-weight: 600;
}
.session-card p {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 400;
    opacity: 0.9;
}
/* Session Page Styles */
.session-header {
    text-align: center;
    margin-bottom: 2rem;
}

.exercise-card {
    background: linear-gradient(120deg, #ffffff 0%, #f8fafc 100%);
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 20px rgba(60, 72, 88, 0.1);
    text-align: center;
}

.exercise-card h2 {
    color: #1e293b;
    margin-bottom: 1rem;
    font-size: 2rem;
}

.set-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2rem;
    padding: 1rem;
    background: #f1f5f9;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    color: #334155;
}

.action-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.success-btn, .fail-btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 120px;
}

.success-btn {
    background: linear-gradient(120deg, #10b981 0%, #059669 100%);
    color: white;
}

.success-btn:hover {
    background: linear-gradient(120deg, #059669 0%, #047857 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(16, 185, 129, 0.3);
}

.fail-btn {
    background: linear-gradient(120deg, #ef4444 0%, #dc2626 100%);
    color: white;
}

.fail-btn:hover {
    background: linear-gradient(120deg, #dc2626 0%, #b91c1c 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(239, 68, 68, 0.3);
}

.rest-timer {
    background: linear-gradient(120deg, #3b82f6 0%, #1d4ed8 100%);
    color: white;
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 2rem;
    text-align: center;
    box-shadow: 0 4px 20px rgba(59, 130, 246, 0.2);
}

.rest-timer h3 {
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.timer-display {
    font-size: 3rem;
    font-weight: bold;
    margin-bottom: 1rem;
    font-family: 'Courier New', monospace;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: #ffffff;
    transition: width 1s linear;
    border-radius: 4px;
}

.exercise-list {
    margin-top: 2rem;
}

.exercise-list h3 {
    color: #1e293b;
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.exercise-scroll {
    display: flex;
    gap: 1rem;
    overflow-x: auto;
    padding: 1rem 0;
    scrollbar-width: thin;
    scrollbar-color: #cbd5e1 #f1f5f9;
}

.exercise-scroll::-webkit-scrollbar {
    height: 6px;
}

.exercise-scroll::-webkit-scrollbar-track {
    background: #f1f5f9;
    border-radius: 3px;
}

.exercise-scroll::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 3px;
}

.exercise-btn {
    min-width: 140px;
    padding: 1rem;
    background: linear-gradient(120deg, #f8fafc 0%, #e2e8f0 100%);
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.exercise-btn:hover {
    background: linear-gradient(120deg, #e2e8f0 0%, #cbd5e1 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.exercise-btn.active {
    background: linear-gradient(120deg, #6366f1 0%, #4f46e5 100%);
    color: white;
    border-color: #6366f1;
}

.exercise-name {
    font-weight: 600;
    font-size: 0.9rem;
}

.exercise-progress {
    font-size: 0.8rem;
    opacity: 0.8;
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal-content {
    background: white;
    padding: 2rem;
    border-radius: 16px;
    text-align: center;
    max-width: 400px;
    width: 90%;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.modal-content h3 {
    color: #1e293b;
    margin-bottom: 1.5rem;
    font-size: 1.3rem;
}

.modal-content input {
    width: 100%;
    padding: 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.modal-content input:focus {
    outline: none;
    border-color: #6366f1;
}

.modal-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.modal-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 100px;
}

.modal-btn:not(.cancel) {
    background: linear-gradient(120deg, #6366f1 0%, #4f46e5 100%);
    color: white;
}

.modal-btn:not(.cancel):hover {
    background: linear-gradient(120deg, #4f46e5 0%, #4338ca 100%);
    transform: translateY(-1px);
}

.modal-btn.cancel {
    background: #f1f5f9;
    color: #64748b;
    border: 1px solid #e2e8f0;
}

.modal-btn.cancel:hover {
    background: #e2e8f0;
}

/* Recent sets and back button */
.recent-sets {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.set-chip {
    padding: 0.35rem 0.6rem;
    background: linear-gradient(120deg, #eef2ff 0%, #e6eefc 100%);
    border: 1px solid #dbeafe;
    border-radius: 999px;
    font-size: 0.9rem;
    color: #0f172a;
    box-shadow: 0 2px 8px rgba(15, 23, 42, 0.06);
}

.back-btn {
    padding: 0.85rem 1rem;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
    background: linear-gradient(120deg, #f3f4f6 0%, #e5e7eb 100%);
    color: #111827;
    border: 1px solid #e5e7eb;
    min-width: 120px;
}

.back-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

button.disabled, .disabled {
    opacity: 0.5;
    cursor: default;
    transform: none !important;
    box-shadow: none !important;
    pointer-events: none;
}

/* Top Back Button */
.top-back-btn {
    position: absolute;
    left: 18px;
    top: 18px;
    background: rgba(255,255,255,0.9);
    border: none;
    border-radius: 8px;
    padding: 6px 10px;
    font-size: 1.1rem;
    cursor: pointer;
    box-shadow: 0 4px 14px rgba(2,6,23,0.08);
}

@media (max-width: 700px) {
    .sessions-grid {
        grid-template-columns: 1fr;
        grid-template-rows: repeat(6, 1fr);
    }
    .container {
        padding: 8px;
    }
    .action-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .success-btn, .fail-btn {
        width: 100%;
        max-width: 200px;
    }
    
    .set-info {
        flex-direction: column;
        gap: 0.5rem;
        text-align: center;
    }
    
    .timer-display {
        font-size: 2.5rem;
    }
    
    .exercise-scroll {
        gap: 0.5rem;
    }
    
    .exercise-btn {
        min-width: 120px;
        padding: 0.75rem;
    }
    
    .top-back-btn {
        left: 10px;
        top: 10px;
    }
}