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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Navbar */
.navbar {
    background: var(--card-bg);
    box-shadow: var(--shadow);
    padding: 1rem 0;
    margin-bottom: 2rem;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-user {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Auth Container */
.auth-container {
    max-width: 450px;
    margin: 4rem auto;
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.auth-tabs {
    display: flex;
    border-bottom: 2px solid var(--border-color);
}

.tab-btn {
    flex: 1;
    padding: 1rem;
    background: none;
    border: none;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.3s;
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
    margin-bottom: -2px;
}

.tab-content {
    display: none;
    padding: 2rem;
}

.tab-content.active {
    display: block;
}

.auth-form h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    text-align: center;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    background-color: var(--card-bg);
    color: var(--text-primary);
    transition: all 0.3s ease;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.form-group input:hover,
.form-group select:hover,
.form-group textarea:hover {
    border-color: #cbd5e1;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    background-color: #ffffff;
}

.form-group textarea {
    min-height: 100px;
    resize: vertical;
    line-height: 1.6;
    padding: 1rem;
}

.form-group textarea::placeholder {
    color: #94a3b8;
    opacity: 0.7;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

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

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

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

.btn-secondary:hover {
    background: var(--text-primary);
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

/* Step Cards */
.step-card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-lg);
}

.step-card h2 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.75rem;
}

.step-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* Upload Area */
.upload-area {
    border: 3px dashed var(--border-color);
    border-radius: 12px;
    padding: 3rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    margin-bottom: 1.5rem;
    background: var(--bg-color);
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: #f1f5f9;
}

.upload-placeholder svg {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.upload-placeholder p {
    margin: 0.5rem 0;
    color: var(--text-secondary);
}

.upload-hint {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Status Messages */
.status-message {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 8px;
    display: none;
}

.status-message.success {
    background: #d1fae5;
    color: #065f46;
    display: block;
}

.status-message.error {
    background: #fee2e2;
    color: #991b1b;
    display: block;
}

.error-message {
    color: var(--error-color);
    margin-top: 1rem;
    font-size: 0.875rem;
}

/* Loading Spinner */
.loading-spinner {
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 2rem auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Analysis Display */
.analysis-display {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 2rem;
    margin-top: 1.5rem;
}

.body-image-preview {
    width: 100%;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.analysis-text {
    background: var(--bg-color);
    padding: 1.5rem;
    border-radius: 12px;
}

.analysis-text h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.analysis-content {
    color: var(--text-secondary);
    line-height: 1.8;
    white-space: pre-wrap;
}

/* Goals Display */
.goals-display {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.goal-item {
    background: var(--bg-color);
    padding: 1.5rem;
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.goal-item strong {
    color: var(--text-primary);
    display: block;
    margin-bottom: 0.5rem;
}

/* Workout Plan */
.workout-plan {
    margin-top: 1.5rem;
}

.workout-content {
    background: var(--bg-color);
    padding: 2rem;
    border-radius: 12px;
    line-height: 1.8;
    color: var(--text-secondary);
    white-space: pre-wrap;
    margin-bottom: 1.5rem;
    max-height: 600px;
    overflow-y: auto;
}

.workout-content h3,
.workout-content h4 {
    color: var(--text-primary);
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.workout-content ul,
.workout-content ol {
    margin-left: 2rem;
    margin-top: 0.5rem;
}

.workout-content li {
    margin-bottom: 0.5rem;
}

.workout-actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.workout-actions .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

/* Info Box */
.info-box {
    background: #e0e7ff;
    border-left: 4px solid var(--primary-color);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.info-box strong {
    color: var(--text-primary);
    display: block;
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.info-box ul {
    margin-left: 1.5rem;
    margin-top: 0.5rem;
}

.info-box li {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

/* Form Hints */
.form-hint {
    display: block;
    margin-top: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-style: italic;
    line-height: 1.4;
}

/* Checkbox grid styling */
.checkbox-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.75rem;
    margin-top: 0.75rem;
}

.checkbox-label {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-color);
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: normal;
}

.checkbox-label:hover {
    background-color: #f1f5f9;
    border-color: #cbd5e1;
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.checkbox-label input[type="checkbox"] {
    width: auto;
    margin-right: 0.75rem;
    cursor: pointer;
    accent-color: var(--primary-color);
    transform: scale(1.2);
    flex-shrink: 0;
}

.checkbox-label input[type="checkbox"]:checked + span {
    color: var(--primary-color);
    font-weight: 500;
}

.checkbox-label:has(input[type="checkbox"]:checked) {
    background-color: #e0e7ff;
    border-color: var(--primary-color);
}

.checkbox-label span {
    flex: 1;
    color: var(--text-primary);
}

/* Horizontal rule styling */
hr {
    border: none;
    border-top: 2px solid var(--border-color);
    margin: 2rem 0;
}

/* Section headers in forms */
.goals-form h3 {
    color: var(--text-primary);
    font-size: 1.25rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }

    .nav-container {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }

    .analysis-display {
        grid-template-columns: 1fr;
    }

    .goals-display {
        grid-template-columns: 1fr;
    }

    .step-card {
        padding: 1.5rem;
    }
}