/* ========================================
   MathLoo Portfolio - Main Stylesheet
   Theme: Modern Violet
   ======================================== */

/* CSS Variables */
:root {
    /* Primary Colors - Violet Theme */
    --primary-50: #faf5ff;
    --primary-100: #f3e8ff;
    --primary-200: #e9d5ff;
    --primary-300: #d8b4fe;
    --primary-400: #c084fc;
    --primary-500: #a855f7;
    --primary-600: #9333ea;
    --primary-700: #7c3aed;
    --primary-800: #6b21a8;
    --primary-900: #581c87;

    /* Neutral Colors */
    --neutral-50: #fafafa;
    --neutral-100: #f5f5f5;
    --neutral-200: #e5e5e5;
    --neutral-300: #d4d4d4;
    --neutral-400: #a3a3a3;
    --neutral-500: #737373;
    --neutral-600: #525252;
    --neutral-700: #404040;
    --neutral-800: #262626;
    --neutral-900: #171717;

    /* Light Theme (default) */
    --text-primary: var(--neutral-800);
    --text-secondary: var(--neutral-600);
    --text-muted: var(--neutral-500);
    --background: #fdfbff;
    --surface: #ffffff;
    --surface-elevated: #f8f5ff;
    --border: #ede9fe;
    --navbar-bg: rgba(255, 255, 255, 0.9);
    --hero-gradient-color: var(--primary-100);
    --card-hover-border: var(--primary-200);
    --accent-text: var(--primary-600);
    --accent-bg: var(--primary-100);
    --footer-bg: var(--neutral-900);
    --footer-border: var(--neutral-800);

    /* Typography */
    --font-display: 'Space Grotesk', sans-serif;
    --font-body: 'Inter', sans-serif;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0;
    --radius-md: 0;
    --radius-lg: 0;
    --radius-xl: 0;
    --radius-2xl: 0;
    --radius-full: 0;

    /* Shadows - Light Theme */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
    --shadow-violet: 0 10px 40px -10px rgba(147, 51, 234, 0.3);
    --shadow-glow: none;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
}

/* Dark Theme */
[data-theme="dark"] {
    --text-primary: #f5f5f5;
    --text-secondary: #a8a3b3;
    --text-muted: #7a7485;
    --background: #0f0a1a;
    --surface: #1a1225;
    --surface-elevated: #241a33;
    --border: #2d2240;
    --navbar-bg: rgba(15, 10, 26, 0.85);
    --hero-gradient-color: var(--primary-900);
    --card-hover-border: var(--primary-700);
    --accent-text: var(--primary-400);
    --accent-bg: rgba(168, 85, 247, 0.15);
    --footer-bg: #080510;
    --footer-border: #2d2240;

    /* Shadows - Dark Theme */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
    --shadow-violet: 0 10px 40px -10px rgba(168, 85, 247, 0.4);
    --shadow-glow: 0 0 30px rgba(168, 85, 247, 0.15);
}

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

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}

body {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 300ms ease, color 300ms ease;
}

main {
    flex: 1;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

ul {
    list-style: none;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
}

.section-title {
    font-size: 2rem;
    margin-bottom: var(--spacing-xl);
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.section-title::before {
    content: '';
    display: inline-block;
    width: 6px;
    height: 1.2em;
    background: linear-gradient(180deg, var(--primary-500), var(--primary-400));
    flex-shrink: 0;
}

.section-title::after {
    display: none;
}

/* ========================================
   Navigation
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--navbar-bg);
    backdrop-filter: blur(20px);
    border-bottom: none;
    transition: var(--transition-base);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: stretch;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) 0;
}

.logo-text {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-600), var(--primary-500));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    gap: 0;
    align-items: stretch;
    height: 100%;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    padding: 0 var(--spacing-md);
    position: relative;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    height: 100%;
}

.nav-link::after {
    display: none;
}

.nav-link:hover {
    color: #ffffff;
    background: var(--primary-400);
}

.nav-link.active {
    color: #ffffff;
    background: var(--primary-600);
}

[data-theme="dark"] .nav-link:hover {
    background: var(--primary-700);
}

[data-theme="dark"] .nav-link.active {
    background: var(--primary-800);
}

[data-theme="dark"] .subnav-link:hover {
    background: var(--primary-700);
}

[data-theme="dark"] .subnav-link.active {
    background: var(--primary-800);
}

.nav-link:hover::after,
.nav-link.active::after {
    display: none;
}

/* Hamburger Menu */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: var(--spacing-sm);
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: var(--radius-full);
    transition: var(--transition-base);
}

/* Theme Toggle */
.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: var(--surface-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition-base);
    margin-left: var(--spacing-md);
}

.theme-toggle:hover {
    background: var(--accent-bg);
    border-color: var(--card-hover-border);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
    transition: var(--transition-base);
}

.theme-toggle:hover svg {
    color: var(--accent-text);
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
    display: none;
}

/* Light theme: show moon (to switch to dark) */
:root .theme-toggle .icon-moon {
    display: block;
}

/* Dark theme: show sun (to switch to light) */
[data-theme="dark"] .theme-toggle .icon-sun {
    display: block;
}

[data-theme="dark"] .theme-toggle .icon-moon {
    display: none;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) 0;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: var(--radius-lg);
    border: none;
    cursor: pointer;
    transition: var(--transition-base);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-600), var(--primary-500));
    color: white;
    box-shadow: var(--shadow-md), var(--shadow-violet);
}

.btn-primary:hover {
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--surface);
    color: var(--primary-600);
    border: 2px solid var(--primary-200);
}

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

/* ========================================
   Hero Section
   ======================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px var(--spacing-lg) var(--spacing-3xl);
    position: relative;
    overflow: hidden;
    background: url('../bgindex.png') center center / cover no-repeat;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to bottom, rgba(0, 0, 0, 0.55) 0%, rgba(0, 0, 0, 0.7) 100%);
    z-index: 0;
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    position: relative;
    z-index: 1;
}

.hero-title {
    margin-bottom: var(--spacing-lg);
}

.greeting {
    display: block;
    font-size: 1.25rem;
    font-weight: 400;
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: var(--spacing-sm);
}

.name {
    display: block;
    font-size: clamp(3rem, 8vw, 5rem);
    font-weight: 700;
    background: linear-gradient(135deg, #ffffff, var(--primary-300), var(--primary-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    filter: drop-shadow(0 0 20px rgba(255, 255, 255, 0.35)) drop-shadow(0 0 60px var(--primary-400));
}

.hero-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.75);
    max-width: 600px;
    margin-bottom: var(--spacing-xl);
    text-shadow: 0 0 15px rgba(255, 255, 255, 0.2), 0 0 40px rgba(0, 0, 0, 0.5);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* ========================================
   Featured Section
   ======================================== */
.featured-section {
    padding: var(--spacing-3xl) var(--spacing-lg);
    background: var(--surface);
}

.featured-card {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    background: var(--surface);
    border-radius: var(--radius-2xl);
    overflow: hidden;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.featured-image {
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.featured-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.placeholder-image {
    width: 100%;
    aspect-ratio: 16/10;
    background: linear-gradient(135deg, var(--primary-500), var(--primary-600));
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
}

.featured-content {
    padding: var(--spacing-2xl) var(--spacing-2xl) var(--spacing-2xl) 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.featured-tag {
    display: inline-block;
    font-size: 0.85rem;
    color: var(--primary-600);
    font-weight: 500;
    margin-bottom: var(--spacing-md);
}

.featured-content h3 {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
}

.featured-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.7;
}

.featured-stats {
    display: flex;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--accent-text);
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ========================================
   Explore Section
   ======================================== */
.explore-section {
    padding: var(--spacing-3xl) var(--spacing-lg);
}

.explore-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-xl);
}

.explore-card {
    display: flex;
    flex-direction: column;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    text-decoration: none;
    color: inherit;
    transition: var(--transition-base);
}

.explore-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl), var(--shadow-glow);
    border-color: var(--card-hover-border);
}

.explore-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
}

.explore-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.explore-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: var(--spacing-lg);
    flex-grow: 1;
}

.explore-link {
    color: var(--accent-text);
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition-fast);
}

.explore-card:hover .explore-link {
    color: var(--primary-400);
}

/* ========================================
   About Section
   ======================================== */
.about-section {
    padding: var(--spacing-3xl) var(--spacing-lg);
}

.about-content {
    max-width: 800px;
}

.about-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    font-size: 1.1rem;
    line-height: 1.8;
}

.about-content strong {
    color: var(--accent-text);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--footer-bg);
    color: var(--neutral-300);
    padding: var(--spacing-2xl) var(--spacing-lg);
    border-top: 1px solid var(--footer-border);
    transition: background-color 300ms ease, border-color 300ms ease;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--footer-border);
}

.footer-brand .logo-text {
    background: linear-gradient(135deg, var(--primary-400), var(--primary-300));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-brand p {
    font-size: 0.9rem;
    color: var(--neutral-500);
    margin-top: var(--spacing-xs);
}

.footer-email {
    display: block;
    margin-top: var(--spacing-sm);
    font-size: 0.9rem;
    color: var(--accent-text);
    transition: var(--transition-fast);
}

.footer-email:hover {
    color: var(--primary-300);
}

.footer-links {
    display: flex;
    gap: var(--spacing-xl);
}

.footer-links a {
    color: var(--neutral-400);
    transition: var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary-400);
}

.footer-bottom {
    padding-top: var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.9rem;
    color: var(--neutral-500);
}

.footer-version {
    font-size: 0.82rem;
    color: var(--neutral-500);
}

.footer-version strong {
    color: var(--neutral-400);
}

/* Update callout - floating tab in hero */
.update-callout {
    position: absolute;
    bottom: 24px;
    right: 24px;
    z-index: 2;
    max-width: 340px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-left: 3px solid var(--primary-400);
    border-radius: var(--radius-lg);
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: left;
}

.update-callout-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-bottom: 2px;
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.82rem;
    color: rgba(255, 255, 255, 0.9);
}

.update-callout-header svg {
    flex-shrink: 0;
    color: var(--primary-300);
}

/* ========================================
   Disclaimer Popup
   ======================================== */

.disclaimer-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
    opacity: 1;
    transition: opacity 0.3s ease;
}

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

.disclaimer-popup {
    background: var(--surface);
    border: 1px solid var(--border);
    max-width: 480px;
    width: 100%;
    padding: var(--spacing-2xl);
    text-align: center;
    box-shadow: var(--shadow-xl);
    animation: disclaimerIn 0.35s ease;
}

@keyframes disclaimerIn {
    from {
        opacity: 0;
        transform: translateY(20px) scale(0.97);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.disclaimer-icon {
    color: #f59e0b;
    margin-bottom: var(--spacing-md);
}

.disclaimer-title {
    font-family: var(--font-display);
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.disclaimer-text {
    font-family: var(--font-body);
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-xl);
}

.disclaimer-btn {
    width: 100%;
    cursor: pointer;
}

.update-callout-date {
    font-size: 0.72rem;
    color: rgba(255, 255, 255, 0.5);
    margin-bottom: 4px;
}

.update-callout-body {
    font-size: 0.78rem;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.5;
    margin: 0;
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 968px) {
    .featured-card {
        grid-template-columns: 1fr;
    }

    .featured-content {
        padding: var(--spacing-xl);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--background);
        flex-direction: column;
        align-items: center;
        justify-content: flex-start;
        padding-top: var(--spacing-2xl);
        gap: var(--spacing-lg);
        transition: var(--transition-slow);
    }

    .nav-menu.active {
        left: 0;
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active .bar:nth-child(1) {
        transform: rotate(45deg) translate(5px, 6px);
    }

    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active .bar:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -6px);
    }

    .hero {
        padding-top: 100px;
    }

    .update-callout {
        position: relative;
        bottom: auto;
        right: auto;
        max-width: 100%;
        margin-top: var(--spacing-lg);
    }

    .hero-cta {
        flex-direction: column;
    }

    .hero-cta .btn {
        width: 100%;
        text-align: center;
    }

    .featured-stats {
        flex-wrap: wrap;
    }

    .footer-content {
        flex-direction: column;
        gap: var(--spacing-xl);
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* ========================================
   Train Animation – border
   ======================================== */
#train-animation-container {
    position: relative;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    padding-bottom: 1px;
    background: #000;
}

/* ========================================
   Page Fade-In (light mode pages)
   Navbar & subnav excluded
   ======================================== */
@keyframes pageFadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}
/* Apply only when no .lv-page (livrees subpages have their own system) */
body:not(:has(.lv-page)) > main,
body:not(:has(.lv-page)) > footer {
    animation: pageFadeIn 0.5s ease both;
}