/* ==========================================================================
   ICGL18 — Neo-Hellenic Academic Design System
   National and Kapodistrian University of Athens
   ========================================================================== */

/* --- Design Tokens --- */
:root {
    /* Primary palette — Aegean & Sandstone */
    --navy:        #0F2540;
    --navy-mid:    #1B3A5C;
    --blue:        #0D5EAF;
    --blue-light:  #3D7EC7;
    --sky:         #E8F0F8;
    --gold:        #C5A34E;
    --gold-light:  #D4B96A;
    --gold-pale:   #F5EDD6;
    --sand:        #F7F4EE;
    --sand-dark:   #EDE8DD;
    --white:       #FFFFFF;
    --off-white:   #FAFAF8;
    --charcoal:    #2C2C2C;
    --text:        #1A1A1A;
    --text-mid:    #4A4A4A;
    --text-light:  #7A7A7A;
    --border:      #D8D3C8;
    --border-light:#E8E4DB;

    /* Typography */
    --font-display: 'Cormorant Garamond', 'Georgia', serif;
    --font-body:    'DM Sans', 'Noto Sans', system-ui, sans-serif;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2.5rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;

    /* Meander pattern (encoded SVG) */
    --meander-pattern: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='40' height='12' viewBox='0 0 40 12'%3E%3Cpath d='M0 0h8v4H4v4h8V4h-4V0h8v8H8v4h8v-4h-4V4h8v8H12v-4H4v4H0V0z' fill='%23C5A34E' fill-opacity='0.3'/%3E%3C/svg%3E");

    /* Transitions */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --transition-fast: 0.2s var(--ease-out);
    --transition-med:  0.4s var(--ease-out);
    --transition-slow: 0.7s var(--ease-out);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.65;
    color: var(--text);
    background-color: var(--off-white);
    overflow-x: hidden;
}

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

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

a:hover {
    color: var(--navy);
}

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

ul {
    list-style: none;
}

/* --- Utilities --- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section {
    padding: var(--space-3xl) 0;
    position: relative;
}

/* --- Meander Decorative Strip --- */
.meander-strip {
    height: 8px;
    background-image: var(--meander-pattern);
    background-repeat: repeat-x;
    background-size: 40px 12px;
    background-position: center;
    opacity: 0.6;
}

.meander-line {
    height: 3px;
    width: 60px;
    background: linear-gradient(90deg, var(--gold), var(--gold-light));
    margin-top: var(--space-md);
    border-radius: 2px;
}

/* --- Navigation --- */
.navbar {
    position: fixed;
    top: 8px;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-light);
    transition: background var(--transition-med), box-shadow var(--transition-med), top var(--transition-med);
}

.navbar.scrolled {
    top: 0;
    background: rgba(255, 255, 255, 0.97);
    box-shadow: 0 1px 12px rgba(15, 37, 64, 0.08);
}

.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-logo {
    display: flex;
    align-items: baseline;
    gap: 2px;
    text-decoration: none;
    flex-shrink: 0;
}

.logo-icgl {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--navy);
    letter-spacing: 0.02em;
}

.logo-18 {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--gold);
    margin-left: 1px;
}

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

.nav-links a {
    font-family: var(--font-body);
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--text-mid);
    padding: 0.4rem 0.7rem;
    border-radius: 6px;
    transition: color var(--transition-fast), background var(--transition-fast);
    white-space: nowrap;
    letter-spacing: 0.01em;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--navy);
    background: var(--sky);
}

/* Language Toggle */
.lang-toggle {
    display: flex;
    align-items: center;
    gap: 4px;
    background: none;
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.35rem 0.65rem;
    cursor: pointer;
    font-family: var(--font-body);
    font-size: 0.78rem;
    font-weight: 600;
    transition: border-color var(--transition-fast);
    flex-shrink: 0;
}

.lang-toggle:hover {
    border-color: var(--gold);
}

.lang-divider {
    color: var(--border);
    font-weight: 400;
}

.lang-option {
    color: var(--text-light);
    transition: color var(--transition-fast);
}

.lang-option.active {
    color: var(--navy);
}

/* Mobile nav toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--navy);
    border-radius: 1px;
    transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-body);
    font-size: 0.88rem;
    font-weight: 600;
    padding: 0.75rem 1.75rem;
    border-radius: 8px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
    letter-spacing: 0.01em;
    text-decoration: none;
}

.btn-primary {
    background: var(--navy);
    color: var(--white);
    border-color: var(--navy);
}

.btn-primary:hover {
    background: var(--navy-mid);
    border-color: var(--navy-mid);
    color: var(--white);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(15, 37, 64, 0.2);
}

.btn-outline {
    background: transparent;
    color: var(--navy);
    border-color: var(--navy);
}

.btn-outline:hover {
    background: var(--navy);
    color: var(--white);
    transform: translateY(-1px);
}

.btn-disabled {
    opacity: 0.5;
    pointer-events: none;
}

/* --- Hero Section --- */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 120px var(--space-lg) var(--space-3xl);
    overflow: hidden;
    background: var(--navy);
}

.hero-bg {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.hero-columns {
    position: absolute;
    inset: 0;
    display: flex;
    justify-content: space-around;
    opacity: 0.04;
}

.hero-columns .column {
    width: 40px;
    height: 100%;
    background: repeating-linear-gradient(
        180deg,
        var(--white) 0px,
        var(--white) 8px,
        transparent 8px,
        transparent 12px
    );
    border-radius: 20px 20px 0 0;
    position: relative;
}

.hero-columns .column::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 56px;
    height: 18px;
    border-radius: 4px;
    background: var(--white);
}

.hero-gradient {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 60% at 50% 50%, rgba(13, 94, 175, 0.15) 0%, transparent 70%),
        radial-gradient(ellipse 50% 80% at 80% 20%, rgba(197, 163, 78, 0.1) 0%, transparent 60%);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
}

.hero-badge {
    display: inline-block;
    font-family: var(--font-body);
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--gold);
    border: 1px solid rgba(197, 163, 78, 0.3);
    padding: 0.5rem 1.25rem;
    border-radius: 100px;
    margin-bottom: var(--space-xl);
    opacity: 0;
    animation: fadeInUp 0.8s var(--ease-out) 0.2s forwards;
}

.hero-title {
    margin-bottom: var(--space-xl);
    opacity: 0;
    animation: fadeInUp 0.8s var(--ease-out) 0.4s forwards;
}

.hero-title-main {
    display: block;
    font-family: var(--font-display);
    font-size: clamp(3rem, 7vw, 5.5rem);
    font-weight: 700;
    color: var(--white);
    letter-spacing: -0.01em;
    line-height: 1.05;
}

.hero-meta {
    display: flex;
    justify-content: center;
    gap: var(--space-xl);
    margin-bottom: var(--space-lg);
    opacity: 0;
    animation: fadeInUp 0.8s var(--ease-out) 0.6s forwards;
}

.hero-meta-item {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-body);
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.75);
}

.hero-meta-item svg {
    opacity: 0.6;
    flex-shrink: 0;
}

/* University logo bar — fixed top-right below navbar */
.uni-logo-bar {
    position: fixed;
    top: 72px;
    right: 0;
    z-index: 999;
    display: flex;
    justify-content: flex-end;
    padding: 8px 24px;
}

.uni-logo-bar img {
    max-height: 80px;
    width: auto;
    background: var(--white);
    padding: 6px 14px;
    border-radius: 8px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    opacity: 0;
    animation: fadeInUp 0.8s var(--ease-out) 0.9s forwards;
}

.hero-actions .btn-primary {
    background: var(--gold);
    border-color: var(--gold);
    color: var(--navy);
}

.hero-actions .btn-primary:hover {
    background: var(--gold-light);
    border-color: var(--gold-light);
    box-shadow: 0 4px 20px rgba(197, 163, 78, 0.3);
}

.hero-actions .btn-outline {
    color: var(--white);
    border-color: rgba(255, 255, 255, 0.3);
}

.hero-actions .btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
    color: var(--white);
}

.hero-scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    animation: fadeIn 1s var(--ease-out) 1.5s forwards;
}

.scroll-line {
    width: 1px;
    height: 48px;
    background: linear-gradient(180deg, rgba(197, 163, 78, 0.6), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

/* --- Section Headers --- */
.section-header {
    margin-bottom: var(--space-2xl);
}

.section-number {
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gold);
    display: block;
    margin-bottom: var(--space-xs);
    letter-spacing: 0.05em;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    color: var(--navy);
}

.section-intro {
    font-size: 1.05rem;
    color: var(--text-mid);
    max-width: 700px;
    margin-bottom: var(--space-2xl);
    line-height: 1.7;
}

.section-label {
    font-family: var(--font-display);
    font-size: clamp(1.8rem, 3.5vw, 2.5rem);
    font-weight: 700;
    color: var(--navy);
    margin-bottom: var(--space-lg);
}

/* --- Animations --- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(24px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.4; transform: scaleY(0.7); transform-origin: top; }
    50% { opacity: 1; transform: scaleY(1); }
}

/* --- Scroll-triggered reveal --- */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}