/* ============================================================
   NSVAIR Alumni Portal - Design System
   CSS Custom Properties, Typography, Base Styles
   ============================================================ */

/* Google Fonts Import */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Outfit:wght@300;400;500;600;700;800;900&display=swap');

/* ============================================================
   CSS Custom Properties (Design Tokens)
   ============================================================ */
:root {
    /* ---- Brand Colors ---- */
    --blue-50: #eff6ff;
    --blue-100: #dbeafe;
    --blue-200: #bfdbfe;
    --blue-300: #93c5fd;
    --blue-400: #60a5fa;
    --blue-500: #3b82f6;
    --blue-600: #2563eb;
    --blue-700: #1d4ed8;
    --blue-800: #1e40af;
    --blue-900: #1e3a8a;

    /* ---- Background Colors (Light Theme Default) ---- */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-surface: #ffffff;
    --bg-elevated: #ffffff;
    --bg-glass: rgba(255, 255, 255, 0.75);
    --bg-glass-heavy: rgba(255, 255, 255, 0.9);

    /* ---- Text Colors (Light Theme Default) ---- */
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-tertiary: #475569;
    --text-muted: #64748b;
    --text-inverse: #ffffff;
    --text-link: var(--blue-600);

    /* ---- Status Colors ---- */
    --success: #10b981;
    --success-bg: rgba(16, 185, 129, 0.12);
    --warning: #f59e0b;
    --warning-bg: rgba(245, 158, 11, 0.12);
    --error: #ef4444;
    --error-bg: rgba(239, 68, 68, 0.12);
    --info: #06b6d4;
    --info-bg: rgba(6, 182, 212, 0.12);

    /* ---- Accent / Gradient ---- */
    --gradient-primary: linear-gradient(135deg, var(--blue-600), var(--blue-400));
    --gradient-accent: linear-gradient(135deg, #667eea, #764ba2);
    --gradient-success: linear-gradient(135deg, #10b981, #34d399);
    --gradient-warm: linear-gradient(135deg, #f59e0b, #f97316);
    --gradient-danger: linear-gradient(135deg, #ef4444, #f87171);
    --gradient-hero: linear-gradient(135deg, var(--blue-50) 0%, #e0e7ff 50%, var(--bg-primary) 100%);

    /* ---- Border ---- */
    --border-color: rgba(15, 23, 42, 0.12);
    --border-light: rgba(15, 23, 42, 0.06);
    --border-focus: var(--blue-500);
}

/* ============================================================
   Dark Theme Overrides
   ============================================================ */
[data-theme="dark"] {
    /* ---- Background Colors (Dark Theme) ---- */
    --bg-primary: #0a0f1c;
    --bg-secondary: #111827;
    --bg-tertiary: #1a2332;
    --bg-surface: #1e293b;
    --bg-elevated: #253348;
    --bg-glass: rgba(17, 24, 39, 0.75);
    --bg-glass-heavy: rgba(10, 15, 28, 0.9);

    /* ---- Text Colors (Dark Theme) ---- */
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-tertiary: #64748b;
    --text-muted: #475569;
    --text-inverse: #0f172a;
    --text-link: var(--blue-400);

    /* ---- Gradient (Dark Theme) ---- */
    --gradient-hero: linear-gradient(135deg, var(--bg-primary) 0%, #0c1a3a 50%, var(--bg-secondary) 100%);

    /* ---- Border (Dark Theme) ---- */
    --border-color: rgba(148, 163, 184, 0.12);
    --border-light: rgba(148, 163, 184, 0.06);
}

:root {
    /* ---- Typography ---- */
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Outfit', 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* ---- Font Sizes ---- */
    --text-xs: 0.75rem;
    /* 12px */
    --text-sm: 0.875rem;
    /* 14px */
    --text-base: 1rem;
    /* 16px */
    --text-lg: 1.125rem;
    /* 18px */
    --text-xl: 1.25rem;
    /* 20px */
    --text-2xl: 1.5rem;
    /* 24px */
    --text-3xl: 1.875rem;
    /* 30px */
    --text-4xl: 2.25rem;
    /* 36px */
    --text-5xl: 3rem;
    /* 48px */
    --text-6xl: 3.75rem;
    /* 60px */

    /* ---- Spacing ---- */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;

    /* ---- Border Radius ---- */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-2xl: 32px;
    --radius-full: 9999px;

    /* ---- Shadows ---- */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.35);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 30px rgba(59, 130, 246, 0.3);
    --shadow-focus: 0 0 0 3px rgba(59, 130, 246, 0.35);

    /* ---- Transitions ---- */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;
    --transition-spring: 350ms cubic-bezier(0.34, 1.56, 0.64, 1);

    /* ---- Glass Effect ---- */
    --glass-blur: blur(16px);
    --glass-saturate: saturate(180%);

    /* ---- Z-Index Scale ---- */
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-fixed: 300;
    --z-overlay: 400;
    --z-modal: 500;
    --z-popover: 600;
    --z-toast: 700;

    /* ---- Layout ---- */
    --sidebar-width: 280px;
    --sidebar-collapsed: 72px;
    --header-height: 72px;
    --max-content-width: 1400px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    font-weight: 400;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    min-height: 100vh;
}

/* ---- Typography Base ---- */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

h1 {
    font-size: var(--text-5xl);
    font-weight: 800;
}

h2 {
    font-size: var(--text-4xl);
    font-weight: 700;
}

h3 {
    font-size: var(--text-3xl);
}

h4 {
    font-size: var(--text-2xl);
}

h5 {
    font-size: var(--text-xl);
}

h6 {
    font-size: var(--text-lg);
}

p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-4);
}

a {
    color: var(--text-link);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--blue-300);
}

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

ul,
ol {
    list-style: none;
}

/* ---- Selection ---- */
::selection {
    background: var(--blue-500);
    color: #fff;
}

/* ---- Scrollbar ---- */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-elevated);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--blue-700);
}

/* ---- Focus Styles ---- */
:focus-visible {
    outline: 2px solid var(--blue-500);
    outline-offset: 2px;
}

/* ============================================================
   Utility Classes
   ============================================================ */
.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.text-right {
    text-align: right;
}

.font-display {
    font-family: var(--font-display);
}

.font-body {
    font-family: var(--font-body);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.container {
    width: 100%;
    max-width: var(--max-content-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.flex {
    display: flex;
}

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

.items-center {
    align-items: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-2 {
    gap: var(--space-2);
}

.gap-4 {
    gap: var(--space-4);
}

.gap-6 {
    gap: var(--space-6);
}

/* ---- Loading Spinner ---- */
.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--blue-500);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

.spinner-sm {
    width: 20px;
    height: 20px;
    border-width: 2px;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* ---- Fade In ---- */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(12px);
    }

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

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

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

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }

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

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }

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

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.6;
    }
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0px);
    }

    50% {
        transform: translateY(-20px);
    }
}

@keyframes glow {

    0%,
    100% {
        box-shadow: 0 0 20px rgba(59, 130, 246, 0.3);
    }

    50% {
        box-shadow: 0 0 40px rgba(59, 130, 246, 0.5);
    }
}

.animate-fade-in {
    animation: fadeIn 0.5s ease forwards;
}

.animate-fade-up {
    animation: fadeInUp 0.6s ease forwards;
}

.animate-slide-left {
    animation: slideInLeft 0.5s ease forwards;
}

.animate-slide-right {
    animation: slideInRight 0.5s ease forwards;
}

.animate-scale {
    animation: scaleIn 0.35s ease forwards;
}

.animate-pulse {
    animation: pulse 2s ease-in-out infinite;
}