/* ========================================
   Titanium Science Club Workshop Registration
   Sleek, Modern Design System (Apple/Google inspired)
   ======================================== */

/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ========================================
   CSS Variables - Design Tokens
   ======================================== */
:root {
    /* Primary Brand Colors - Refined Blue */
    --primary-50: #f0f7ff;
    --primary-100: #e0effe;
    --primary-200: #bae0fd;
    --primary-300: #7cc5f8;
    --primary-400: #36a6f1;
    --primary-500: #0b8ce9;
    /* Google Blue-ish */
    --primary-600: #006ec1;
    --primary-700: #00589c;

    /* Secondary/Accent */
    --accent-500: #6366f1;
    /* Indigo */

    /* Semantic Colors */
    --success-surface: #ecfdf5;
    --success-text: #047857;
    --success-icon: #10b981;

    --warning-surface: #fffbeb;
    --warning-text: #b45309;

    --error-surface: #fef2f2;
    --error-text: #b91c1c;

    /* Neutrals - Apple-style grays */
    --white: #ffffff;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;

    /* Spacing System */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;

    /* Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows - Soft & Diffuse */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.025);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 10px 10px -5px rgba(0, 0, 0, 0.02);

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

/* ========================================
   Reset & Base
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-sans);
    background-color: var(--gray-50);
    color: var(--gray-900);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--primary-600);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--primary-700);
}

/* ========================================
   Header
   ======================================== */
.header {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--gray-200);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--gray-900);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    letter-spacing: -0.025em;
}

.logo i {
    color: var(--primary-600);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    list-style: none;
}

.nav-links a {
    color: var(--gray-600);
    font-weight: 500;
    font-size: 0.9375rem;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-md);
    transition: all 0.2s;
}

.nav-links a:hover {
    color: var(--gray-900);
    background-color: var(--gray-100);
}

/* ========================================
   Layout
   ======================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.container-narrow {
    max-width: 768px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.main-content {
    padding: 3rem 0;
    min-height: 80vh;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    text-align: center;
    padding: 4rem 0 3rem;
    margin-bottom: 2rem;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    color: var(--gray-900);
    margin-bottom: 1rem;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--gray-500);
    max-width: 600px;
    margin: 0 auto 1.5rem;
    font-weight: 400;
}

/* ========================================
   Cards
   ======================================== */
.card {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    overflow: hidden;
}

.card-header {
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--gray-100);
    background: var(--white);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--gray-900);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.card-body {
    padding: 2rem;
}

/* ========================================
   Workshops Grid
   ======================================== */
.workshops-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 2rem;
}

.workshop-card {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.workshop-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-200);
}

.workshop-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--gray-100);
}

.workshop-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 0.75rem;
    line-height: 1.3;
}

.workshop-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.workshop-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.025em;
    text-transform: uppercase;
}

.workshop-badge.free {
    background-color: var(--success-surface);
    color: var(--success-text);
}

.workshop-badge.paid {
    background-color: var(--primary-50);
    color: var(--primary-700);
}

.workshop-body {
    padding: 1.5rem;
    flex-grow: 1;
}

.workshop-detail {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.9375rem;
    color: var(--gray-600);
}

.workshop-detail-icon {
    color: var(--gray-400);
    width: 1.25rem;
    text-align: center;
    margin-top: 0.125rem;
}

.workshop-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--gray-100);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--gray-50);
}

.capacity-info {
    font-size: 0.875rem;
    color: var(--gray-500);
    font-weight: 500;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    font-size: 0.9375rem;
    font-weight: 500;
    border-radius: var(--radius-lg);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
    line-height: 1.25;
}

.btn-primary {
    background-color: var(--gray-900);
    /* Apple style black button */
    color: var(--white);
}

.btn-primary:hover {
    background-color: var(--gray-800);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--white);
    border-color: var(--gray-200);
    color: var(--gray-700);
}

.btn-secondary:hover {
    background-color: var(--gray-50);
    border-color: var(--gray-300);
    color: var(--gray-900);
}

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

.btn-success:hover {
    background-color: var(--success-text);
}

.btn-outline {
    background: transparent;
    border-color: var(--gray-300);
    color: var(--gray-700);
}

.btn-outline:hover {
    border-color: var(--gray-900);
    color: var(--gray-900);
}

.btn-lg {
    padding: 0.875rem 1.5rem;
    font-size: 1rem;
}

.btn-block {
    width: 100%;
    display: flex;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
}

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

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--gray-700);
    margin-bottom: 0.5rem;
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    line-height: 1.5;
    color: var(--gray-900);
    background-color: var(--white);
    border: 1px solid var(--gray-300);
    border-radius: var(--radius-md);
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
    outline: 0;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px rgba(11, 140, 233, 0.15);
}

.form-control::placeholder {
    color: var(--gray-400);
}

.form-check {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.form-check-input {
    width: 1.125rem;
    height: 1.125rem;
    border-radius: 0.25rem;
    border: 1px solid var(--gray-300);
    cursor: pointer;
}

.form-check-label {
    font-size: 0.9375rem;
    color: var(--gray-700);
    cursor: pointer;
}

.form-error {
    font-size: 0.8125rem;
    color: var(--error-text);
    margin-top: 0.375rem;
}

/* ========================================
   Alerts
   ======================================== */
.messages {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    width: 100%;
    max-width: 400px;
}

.alert {
    padding: 1rem 1.25rem;
    border-radius: var(--radius-lg);
    font-size: 0.9375rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    border: 1px solid transparent;
    animation: slideIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.alert-success {
    background-color: var(--white);
    border-color: var(--success-surface);
    color: var(--success-text);
    border-left: 4px solid var(--success-icon);
}

.alert-error {
    background-color: var(--white);
    border-color: var(--error-surface);
    color: var(--error-text);
    border-left: 4px solid var(--error-text);
}

.alert-info {
    background-color: var(--white);
    border-color: var(--primary-100);
    color: var(--primary-700);
    border-left: 4px solid var(--primary-500);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background-color: var(--white);
    border-top: 1px solid var(--gray-200);
    padding: 3rem 0;
    margin-top: auto;
}

.footer-content {
    text-align: center;
}

.footer-logo {
    font-weight: 700;
    font-size: 1.125rem;
    color: var(--gray-900);
    margin-bottom: 0.5rem;
}

.footer p {
    color: var(--gray-500);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

/* ========================================
   Utilities
   ======================================== */
.text-center {
    text-align: center;
}

.text-muted {
    color: var(--gray-500);
}

.text-primary {
    color: var(--primary-600);
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }

    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@media (max-width: 640px) {
    .hero-title {
        font-size: 2rem;
    }

    .workshops-grid {
        grid-template-columns: 1fr;
    }

    .messages {
        left: 1rem;
        right: 1rem;
        width: auto;
    }
}