/**
 * style.css - Main Stylesheet
 * 프로그래머 문호영 - Corporate Website
 *
 * Color Scheme: Cosmic
 * Style: Modern with Skillshare-inspired UI
 *
 * @package TION_Corporate
 * @version 1.0.0
 */

/* ==========================================================================
   CSS Custom Properties (Variables)
   ========================================================================== */

:root {
    /* Primary Colors - Cosmic Theme */
    --color-primary: #667eea;
    --color-primary-dark: #5a6fd6;
    --color-primary-light: #7b8fed;
    --color-secondary: #764ba2;
    --color-secondary-dark: #6a4291;
    --color-secondary-light: #8657b3;
    --color-accent: #f093fb;
    --color-accent-dark: #e67df0;
    --color-accent-light: #f5a9fc;

    /* Gradient Definitions */
    --gradient-cosmic: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-cosmic-reverse: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
    --gradient-nebula: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    --gradient-aurora: linear-gradient(135deg, #667eea 0%, #f093fb 50%, #764ba2 100%);
    --gradient-dark: linear-gradient(180deg, #1a1a2e 0%, #0d0d1a 100%);
    --gradient-card: linear-gradient(145deg, rgba(255,255,255,0.05) 0%, rgba(255,255,255,0.02) 100%);

    /* Skillshare Green Accent */
    --color-skillshare: #03C75A;
    --color-skillshare-dark: #02a34a;
    --color-skillshare-light: #04d862;

    /* Neutral Colors */
    --color-white: #ffffff;
    --color-black: #000000;
    --color-gray-50: #f8fafc;
    --color-gray-100: #f1f5f9;
    --color-gray-200: #e2e8f0;
    --color-gray-300: #cbd5e1;
    --color-gray-400: #94a3b8;
    --color-gray-500: #64748b;
    --color-gray-600: #475569;
    --color-gray-700: #334155;
    --color-gray-800: #1e293b;
    --color-gray-900: #0f172a;

    /* Semantic Colors */
    --color-success: #10b981;
    --color-success-bg: rgba(16, 185, 129, 0.1);
    --color-warning: #f59e0b;
    --color-warning-bg: rgba(245, 158, 11, 0.1);
    --color-error: #ef4444;
    --color-error-bg: rgba(239, 68, 68, 0.1);
    --color-info: #3b82f6;
    --color-info-bg: rgba(59, 130, 246, 0.1);

    /* Schedule Category Colors */
    --schedule-general: #667eea;
    --schedule-meeting: #f093fb;
    --schedule-project: #4facfe;
    --schedule-deadline: #ff6b6b;
    --schedule-event: #51cf66;
    --schedule-personal: #ffa94d;
    --schedule-other: #868e96;

    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-dark: #1a1a2e;
    --bg-dark-secondary: #16213e;
    --bg-overlay: rgba(0, 0, 0, 0.5);
    --bg-glass: rgba(255, 255, 255, 0.1);
    --bg-glass-dark: rgba(0, 0, 0, 0.3);

    /* Text Colors */
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-tertiary: #64748b;
    --text-muted: #94a3b8;
    --text-light: #ffffff;
    --text-link: #667eea;
    --text-link-hover: #5a6fd6;

    /* Border Colors */
    --border-light: #e2e8f0;
    --border-medium: #cbd5e1;
    --border-dark: #94a3b8;
    --border-focus: #667eea;

    /* Shadow Definitions */
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px 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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-cosmic: 0 10px 40px rgba(102, 126, 234, 0.3);
    --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.4);
    --shadow-inner: inset 0 2px 4px rgba(0, 0, 0, 0.06);

    /* Typography */
    --font-primary: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', 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 */

    /* Font Weights */
    --font-light: 300;
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;
    --font-black: 900;

    /* Line Heights */
    --leading-none: 1;
    --leading-tight: 1.25;
    --leading-snug: 1.375;
    --leading-normal: 1.5;
    --leading-relaxed: 1.625;
    --leading-loose: 2;

    /* Letter Spacing */
    --tracking-tighter: -0.05em;
    --tracking-tight: -0.025em;
    --tracking-normal: 0;
    --tracking-wide: 0.025em;
    --tracking-wider: 0.05em;
    --tracking-widest: 0.1em;

    /* Spacing Scale */
    --space-0: 0;
    --space-1: 0.25rem;     /* 4px */
    --space-2: 0.5rem;      /* 8px */
    --space-3: 0.75rem;     /* 12px */
    --space-4: 1rem;        /* 16px */
    --space-5: 1.25rem;     /* 20px */
    --space-6: 1.5rem;      /* 24px */
    --space-8: 2rem;        /* 32px */
    --space-10: 2.5rem;     /* 40px */
    --space-12: 3rem;       /* 48px */
    --space-16: 4rem;       /* 64px */
    --space-20: 5rem;       /* 80px */
    --space-24: 6rem;       /* 96px */

    /* Border Radius */
    --radius-none: 0;
    --radius-sm: 0.25rem;   /* 4px */
    --radius-md: 0.375rem;  /* 6px */
    --radius-lg: 0.5rem;    /* 8px */
    --radius-xl: 0.75rem;   /* 12px */
    --radius-2xl: 1rem;     /* 16px */
    --radius-3xl: 1.5rem;   /* 24px */
    --radius-full: 9999px;

    /* Z-Index Scale */
    --z-base: 0;
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-fixed: 300;
    --z-modal-backdrop: 400;
    --z-modal: 500;
    --z-popover: 600;
    --z-tooltip: 700;
    --z-toast: 800;
    --z-max: 9999;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
    --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);

    /* Container Widths */
    --container-sm: 640px;
    --container-md: 768px;
    --container-lg: 1024px;
    --container-xl: 1200px;
    --container-2xl: 1400px;

    /* Header Height */
    --header-height: 70px;
    --header-height-mobile: 60px;
}

/* ==========================================================================
   Reset & Base Styles
   ========================================================================== */

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

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

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

/* Remove default styles */
ul, ol {
    list-style: none;
}

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

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

button, input, select, textarea {
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
    color: inherit;
    background: none;
    border: none;
    outline: none;
}

button {
    cursor: pointer;
}

table {
    border-collapse: collapse;
    border-spacing: 0;
}

/* Focus visible for accessibility */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Selection styling */
::selection {
    background-color: var(--color-primary);
    color: var(--color-white);
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--color-gray-400);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-gray-500);
}

/* ==========================================================================
   Accessibility
   ========================================================================== */

.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: var(--color-white);
    padding: var(--space-2) var(--space-4);
    z-index: var(--z-max);
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: 0;
}

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

/* ==========================================================================
   Layout
   ========================================================================== */

.container {
    width: 100%;
    max-width: var(--container-xl);
    margin: 0 auto;
    padding: 0 var(--space-5);
}

.container-sm {
    max-width: var(--container-sm);
}

.container-md {
    max-width: var(--container-md);
}

.container-lg {
    max-width: var(--container-lg);
}

.container-2xl {
    max-width: var(--container-2xl);
}

/* Section spacing */
.section {
    padding: var(--space-20) 0;
}

.section-sm {
    padding: var(--space-12) 0;
}

.section-lg {
    padding: var(--space-24) 0;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--space-6);
}

.grid-cols-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-cols-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* Flex utilities */
.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

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

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

.items-start {
    align-items: flex-start;
}

.items-end {
    align-items: flex-end;
}

.justify-center {
    justify-content: center;
}

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

.justify-end {
    justify-content: flex-end;
}

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

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

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

.gap-8 {
    gap: var(--space-8);
}

/* ==========================================================================
   Typography
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-bold);
    line-height: var(--leading-tight);
    color: var(--text-primary);
}

h1 {
    font-size: var(--text-4xl);
    letter-spacing: var(--tracking-tight);
}

h2 {
    font-size: var(--text-3xl);
}

h3 {
    font-size: var(--text-2xl);
}

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

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

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

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

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

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

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

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: var(--space-12);
}

.section-subtitle {
    display: inline-block;
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: var(--tracking-wider);
    margin-bottom: var(--space-2);
    padding: var(--space-1) var(--space-3);
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
    border-radius: var(--radius-full);
}

.section-title {
    font-size: var(--text-4xl);
    font-weight: var(--font-bold);
    margin-bottom: var(--space-4);
    background: var(--gradient-cosmic);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-description {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ==========================================================================
   Header
   ========================================================================== */

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-light);
    z-index: var(--z-fixed);
    transition: all var(--transition-normal);
}

.site-header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    text-decoration: none;
    transition: opacity var(--transition-fast);
}

.logo:hover {
    opacity: 0.8;
}

.logo-icon svg {
    width: 40px;
    height: 40px;
}

.logo-text {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-main {
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--text-secondary);
}

.logo-sub {
    font-size: var(--text-lg);
    font-weight: var(--font-bold);
    background: var(--gradient-cosmic);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Main Navigation */
.main-nav {
    display: flex;
    align-items: center;
}

.nav-list {
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.nav-item {
    position: relative;
}

.nav-item > a {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--text-secondary);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.nav-item > a:hover,
.nav-item.active > a {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.08);
}

.nav-item .badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 18px;
    height: 18px;
    padding: 0 var(--space-1);
    font-size: 10px;
    font-weight: var(--font-bold);
    color: var(--color-white);
    background: var(--color-error);
    border-radius: var(--radius-full);
}

/* Dropdown Menu */
.nav-item.has-dropdown > a::after {
    content: '';
    width: 4px;
    height: 4px;
    border-right: 1.5px solid currentColor;
    border-bottom: 1.5px solid currentColor;
    transform: rotate(45deg);
    margin-top: -2px;
    transition: transform var(--transition-fast);
}

.nav-item.has-dropdown:hover > a::after {
    transform: rotate(-135deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 200px;
    padding: var(--space-2);
    background: var(--color-white);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all var(--transition-fast);
}

.nav-item.has-dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu li a {
    display: block;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.dropdown-menu li a:hover {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.08);
}

/* Header Actions */
.header-actions {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.btn-admin {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.btn-admin:hover {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.1);
}

.action-badge {
    position: absolute;
    top: -4px;
    right: -4px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 18px;
    height: 18px;
    padding: 0 4px;
    font-size: 10px;
    font-weight: var(--font-bold);
    color: var(--color-white);
    background: var(--color-error);
    border-radius: var(--radius-full);
}

/* Mobile Menu Toggle */
.btn-mobile-menu {
    display: none;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    padding: 0;
    background: transparent;
}

.hamburger {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 24px;
    height: 24px;
}

.hamburger span {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--text-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.btn-mobile-menu[aria-expanded="true"] .hamburger span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.btn-mobile-menu[aria-expanded="true"] .hamburger span:nth-child(2) {
    opacity: 0;
}

.btn-mobile-menu[aria-expanded="true"] .hamburger span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Navigation */
.mobile-nav {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-white);
    overflow-y: auto;
    z-index: var(--z-fixed);
}

.mobile-nav.active {
    display: block;
}

.mobile-nav-inner {
    padding: var(--space-6);
}

.mobile-nav-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.mobile-nav-list > li > a,
.mobile-nav-list > li > .submenu-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4);
    font-size: var(--text-lg);
    font-weight: var(--font-medium);
    color: var(--text-primary);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.mobile-nav-list > li > a:hover,
.mobile-nav-list > li > .submenu-toggle:hover {
    background: var(--bg-secondary);
}

.mobile-nav-list .has-submenu .submenu-toggle::after {
    content: '+';
    font-size: var(--text-xl);
    color: var(--text-tertiary);
    transition: transform var(--transition-fast);
}

.mobile-nav-list .has-submenu.open .submenu-toggle::after {
    content: '−';
}

.mobile-nav-list .submenu {
    display: none;
    padding-left: var(--space-4);
    margin-top: var(--space-1);
}

.mobile-nav-list .has-submenu.open .submenu {
    display: block;
}

.mobile-nav-list .submenu a {
    display: block;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-base);
    color: var(--text-secondary);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.mobile-nav-list .submenu a:hover {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.08);
}

.mobile-nav-list .admin-link a {
    color: var(--color-primary);
    font-weight: var(--font-semibold);
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    line-height: 1;
    text-align: center;
    white-space: nowrap;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-primary {
    color: var(--color-white);
    background: var(--gradient-cosmic);
    box-shadow: var(--shadow-cosmic);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.1);
    border: 1px solid transparent;
}

.btn-secondary:hover {
    background: rgba(102, 126, 234, 0.15);
    border-color: var(--color-primary);
}

.btn-outline {
    color: var(--text-primary);
    background: transparent;
    border: 1px solid var(--border-medium);
}

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

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

.btn-ghost:hover {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.08);
}

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

.btn-success:hover {
    background: #0da271;
}

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

.btn-error:hover {
    background: #dc3030;
}

.btn-sm {
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-xs);
}

.btn-lg {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-base);
}

.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
}

.btn-icon.btn-sm {
    width: 32px;
    height: 32px;
}

.btn-icon.btn-lg {
    width: 48px;
    height: 48px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

/* ==========================================================================
   Cards
   ========================================================================== */

.card {
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    overflow: hidden;
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.card-image {
    position: relative;
    overflow: hidden;
    aspect-ratio: 16/9;
}

.card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.card:hover .card-image img {
    transform: scale(1.05);
}

.card-body {
    padding: var(--space-6);
}

.card-title {
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    margin-bottom: var(--space-2);
}

.card-description {
    color: var(--text-secondary);
    margin-bottom: var(--space-4);
}

.card-meta {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

/* Glass Card */
.card-glass {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* Feature Card */
.feature-card {
    padding: var(--space-8);
    text-align: center;
}

.feature-card .icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    margin-bottom: var(--space-4);
    background: var(--gradient-cosmic);
    border-radius: var(--radius-xl);
    color: var(--color-white);
}

.feature-card .icon svg {
    width: 28px;
    height: 28px;
}

/* Project Card (Skillshare-inspired) */
.project-card {
    position: relative;
    border-radius: var(--radius-xl);
    overflow: hidden;
}

.project-card .card-image {
    aspect-ratio: 4/3;
}

.project-card .card-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, transparent 0%, rgba(0, 0, 0, 0.7) 100%);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.project-card:hover .card-overlay {
    opacity: 1;
}

.project-card .card-content {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--space-6);
    color: var(--color-white);
    transform: translateY(20px);
    opacity: 0;
    transition: all var(--transition-normal);
}

.project-card:hover .card-content {
    transform: translateY(0);
    opacity: 1;
}

.project-card .card-category {
    display: inline-block;
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-full);
    margin-bottom: var(--space-2);
}

/* ==========================================================================
   Forms
   ========================================================================== */

.form-group {
    margin-bottom: var(--space-5);
}

.form-label {
    display: block;
    margin-bottom: var(--space-2);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--text-primary);
}

.form-label.required::after {
    content: '*';
    color: var(--color-error);
    margin-left: var(--space-1);
}

.form-control {
    display: block;
    width: 100%;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-base);
    color: var(--text-primary);
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.form-control:hover {
    border-color: var(--border-medium);
}

.form-control:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.15);
}

.form-control::placeholder {
    color: var(--text-muted);
}

.form-control.error {
    border-color: var(--color-error);
}

.form-control.error:focus {
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.15);
}

textarea.form-control {
    min-height: 120px;
    resize: vertical;
}

.form-hint {
    margin-top: var(--space-1);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.form-error {
    margin-top: var(--space-1);
    font-size: var(--text-sm);
    color: var(--color-error);
}

/* Select */
.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%2364748b' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
    background-position: right var(--space-3) center;
    background-repeat: no-repeat;
    background-size: 20px;
    padding-right: var(--space-10);
}

/* Checkbox & Radio */
.form-check {
    display: flex;
    align-items: flex-start;
    gap: var(--space-3);
}

.form-check-input {
    flex-shrink: 0;
    width: 20px;
    height: 20px;
    margin-top: 2px;
    accent-color: var(--color-primary);
    cursor: pointer;
}

.form-check-label {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    cursor: pointer;
}

/* ==========================================================================
   Main Content Area
   ========================================================================== */

.site-main {
    min-height: calc(100vh - var(--header-height));
    padding-top: var(--header-height);
}

/* Page Hero */
.page-hero {
    position: relative;
    padding: var(--space-20) 0;
    background: var(--gradient-nebula);
    color: var(--color-white);
    overflow: hidden;
}

.page-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
    opacity: 0.03;
    pointer-events: none;
}

.page-hero .container {
    position: relative;
    z-index: 1;
}

.page-hero-title {
    font-size: var(--text-5xl);
    font-weight: var(--font-black);
    margin-bottom: var(--space-4);
    color: #ffffff;
    text-shadow:
        0 2px 4px rgba(0, 0, 0, 0.5),
        0 4px 20px rgba(0, 0, 0, 0.4),
        0 0 40px rgba(102, 126, 234, 0.3);
}

.page-hero-description {
    font-size: var(--text-xl);
    color: #ffffff;
    max-width: 600px;
    line-height: 1.8;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
}

/* Breadcrumb - High Visibility */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.95);
    margin-bottom: var(--space-6);
}

.breadcrumb a {
    color: rgba(255, 255, 255, 0.9);
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
    transition: color var(--transition-fast);
}

.breadcrumb a:hover {
    color: #ffffff;
    text-decoration: underline;
}

.breadcrumb span {
    color: rgba(255, 255, 255, 0.75);
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
    background: var(--gradient-dark);
    color: var(--color-white);
    padding-top: var(--space-16);
}

.footer-main {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: var(--space-12);
    padding-bottom: var(--space-12);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    margin-bottom: var(--space-4);
}

.footer-logo .logo-text {
    font-size: var(--text-lg);
    font-weight: var(--font-bold);
}

.footer-description {
    color: rgba(255, 255, 255, 0.85);
    font-size: var(--text-sm);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-5);
}

.footer-social {
    display: flex;
    gap: var(--space-3);
}

.footer-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    color: rgba(255, 255, 255, 0.6);
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.footer-social a:hover {
    color: var(--color-white);
    background: var(--color-primary);
}

.footer-title {
    font-size: var(--text-sm);
    font-weight: var(--font-bold);
    text-transform: uppercase;
    letter-spacing: var(--tracking-wider);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--space-5);
}

.footer-section ul {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.footer-section ul a,
.footer-section ul span {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.85);
    transition: color var(--transition-fast);
}

.footer-section ul a:hover {
    color: var(--color-white);
    text-decoration: underline;
}

.footer-section ul svg {
    flex-shrink: 0;
    opacity: 0.7;
}

.footer-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-6) 0;
}

.footer-legal {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
}

.footer-legal a {
    color: rgba(255, 255, 255, 0.8);
    transition: color var(--transition-fast);
}

.footer-legal a:hover {
    color: var(--color-white);
    text-decoration: underline;
}

.footer-legal .divider {
    color: rgba(255, 255, 255, 0.4);
}

.footer-copyright {
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.7);
    margin: 0;
}

/* Footer Business Info */
.footer-business-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-4);
    padding: var(--space-5) 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    margin-bottom: var(--space-4);
}

.business-info-content {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.75);
}

.business-label {
    font-weight: var(--font-semibold);
    color: rgba(255, 255, 255, 0.9);
}

.business-divider {
    color: rgba(255, 255, 255, 0.3);
}

.business-info-links {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.business-info-links a {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: rgba(255, 255, 255, 0.85);
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.business-info-links a:hover {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

.business-info-links a svg {
    fill: #03C75A;
}

/* Footer Social Icon Colors */
.footer-social a[aria-label="YouTube"] svg {
    fill: #FF0000;
}

.footer-social a[aria-label="네이버 블로그"] svg {
    fill: #03C75A;
}

/* ==========================================================================
   Back to Top Button
   ========================================================================== */

.back-to-top {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    color: var(--color-white);
    background: var(--gradient-cosmic);
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition-normal);
    z-index: var(--z-sticky);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-cosmic);
}

/* ==========================================================================
   Toast Notifications
   ========================================================================== */

.toast-container {
    position: fixed;
    top: calc(var(--header-height) + var(--space-4));
    right: var(--space-4);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    z-index: var(--z-toast);
}

.toast {
    display: flex;
    align-items: flex-start;
    gap: var(--space-3);
    min-width: 300px;
    max-width: 400px;
    padding: var(--space-4);
    background: var(--color-white);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    transform: translateX(100%);
    opacity: 0;
    animation: toast-in 0.3s ease forwards;
}

@keyframes toast-in {
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.toast.toast-out {
    animation: toast-out 0.3s ease forwards;
}

@keyframes toast-out {
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

.toast-icon {
    flex-shrink: 0;
    width: 24px;
    height: 24px;
}

.toast-success .toast-icon {
    color: var(--color-success);
}

.toast-error .toast-icon {
    color: var(--color-error);
}

.toast-warning .toast-icon {
    color: var(--color-warning);
}

.toast-info .toast-icon {
    color: var(--color-info);
}

.toast-content {
    flex: 1;
}

.toast-title {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--text-primary);
    margin-bottom: var(--space-1);
}

.toast-message {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    margin: 0;
}

.toast-close {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    color: var(--text-tertiary);
    background: transparent;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.toast-close:hover {
    color: var(--text-primary);
    background: var(--bg-secondary);
}

/* ==========================================================================
   Modal
   ========================================================================== */

.modal-container {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-4);
    background: var(--bg-overlay);
    backdrop-filter: blur(4px);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
    z-index: var(--z-modal);
}

.modal-container.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-2xl);
    overflow: hidden;
    transform: scale(0.95);
    transition: transform var(--transition-normal);
}

.modal-container.active .modal {
    transform: scale(1);
}

.modal-lg {
    max-width: 800px;
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-5) var(--space-6);
    border-bottom: 1px solid var(--border-light);
}

.modal-title {
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    margin: 0;
}

.modal-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    color: var(--text-tertiary);
    background: transparent;
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    color: var(--text-primary);
    background: var(--bg-secondary);
}

.modal-body {
    padding: var(--space-6);
    overflow-y: auto;
    max-height: calc(90vh - 140px);
}

.modal-footer {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--space-3);
    padding: var(--space-4) var(--space-6);
    border-top: 1px solid var(--border-light);
    background: var(--bg-secondary);
}

/* ==========================================================================
   Utilities
   ========================================================================== */

/* Spacing */
.mt-0 { margin-top: 0; }
.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.pt-0 { padding-top: 0; }
.pt-4 { padding-top: var(--space-4); }
.pt-8 { padding-top: var(--space-8); }

.pb-0 { padding-bottom: 0; }
.pb-4 { padding-bottom: var(--space-4); }
.pb-8 { padding-bottom: var(--space-8); }

/* Display */
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }
.inline-flex { display: inline-flex; }

/* Text utilities */
.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--text-secondary); }
.text-success { color: var(--color-success); }
.text-error { color: var(--color-error); }
.text-muted { color: var(--text-muted); }

.font-medium { font-weight: var(--font-medium); }
.font-semibold { font-weight: var(--font-semibold); }
.font-bold { font-weight: var(--font-bold); }

/* Background utilities */
.bg-white { background-color: var(--color-white); }
.bg-gray { background-color: var(--bg-secondary); }
.bg-dark { background-color: var(--bg-dark); }

/* Border utilities */
.rounded { border-radius: var(--radius-lg); }
.rounded-full { border-radius: var(--radius-full); }

/* Shadow utilities */
.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }

/* Width utilities */
.w-full { width: 100%; }
.max-w-md { max-width: var(--container-md); }
.max-w-lg { max-width: var(--container-lg); }

/* ==========================================================================
   Loading States
   ========================================================================== */

.loading {
    position: relative;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(255, 255, 255, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
}

.spinner {
    width: 24px;
    height: 24px;
    border: 2px solid var(--border-light);
    border-top-color: var(--color-primary);
    border-radius: var(--radius-full);
    animation: spin 0.8s linear infinite;
}

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

/* ==========================================================================
   Empty States
   ========================================================================== */

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-16) var(--space-8);
    text-align: center;
}

.empty-state-icon {
    width: 80px;
    height: 80px;
    margin-bottom: var(--space-6);
    color: var(--text-muted);
    opacity: 0.5;
}

.empty-state-title {
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    color: var(--text-primary);
    margin-bottom: var(--space-2);
}

.empty-state-description {
    color: var(--text-secondary);
    max-width: 400px;
    margin-bottom: var(--space-6);
}

/* ==========================================================================
   Tags & Badges
   ========================================================================== */

.tag {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: var(--font-medium);
    border-radius: var(--radius-full);
    background: var(--bg-secondary);
    color: var(--text-secondary);
}

.tag-primary {
    background: rgba(102, 126, 234, 0.1);
    color: var(--color-primary);
}

.tag-success {
    background: var(--color-success-bg);
    color: var(--color-success);
}

.tag-warning {
    background: var(--color-warning-bg);
    color: var(--color-warning);
}

.tag-error {
    background: var(--color-error-bg);
    color: var(--color-error);
}

.badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 20px;
    height: 20px;
    padding: 0 var(--space-2);
    font-size: var(--text-xs);
    font-weight: var(--font-bold);
    color: var(--color-white);
    background: var(--color-primary);
    border-radius: var(--radius-full);
}

/* ==========================================================================
   Tables
   ========================================================================== */

.table-container {
    overflow-x: auto;
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-light);
}

.table {
    width: 100%;
    border-collapse: collapse;
}

.table th,
.table td {
    padding: var(--space-4);
    text-align: left;
    border-bottom: 1px solid var(--border-light);
}

.table th {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--text-tertiary);
    background: var(--bg-secondary);
    text-transform: uppercase;
    letter-spacing: var(--tracking-wide);
}

.table td {
    font-size: var(--text-sm);
    color: var(--text-primary);
}

.table tbody tr:hover {
    background: var(--bg-secondary);
}

.table tbody tr:last-child td {
    border-bottom: none;
}

/* ==========================================================================
   Tabs
   ========================================================================== */

.tabs {
    display: flex;
    gap: var(--space-1);
    padding: var(--space-1);
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    margin-bottom: var(--space-6);
}

.tab-btn {
    flex: 1;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--text-secondary);
    background: transparent;
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.tab-btn:hover {
    color: var(--text-primary);
}

.tab-btn.active {
    color: var(--text-primary);
    background: var(--color-white);
    box-shadow: var(--shadow-sm);
}

.tab-content {
    display: none;
}

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

/* ==========================================================================
   ANTIGRAVITY Effect Container
   ========================================================================== */

.antigravity-effect {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
    opacity: 0.4;
}

/* Dark mode for certain sections */
.dark-section {
    background: var(--gradient-nebula);
    color: var(--color-white);
}

.dark-section .section-title {
    color: var(--color-white);
    -webkit-text-fill-color: var(--color-white);
}

.dark-section .section-description {
    color: rgba(255, 255, 255, 0.7);
}