/* ═════════════════════════════════════════════════════════════════════════════ */
/* GLOBAL STYLES */
/* ═════════════════════════════════════════════════════════════════════════════ */

:root {
    --navy: #0a192f;
    --charcoal: #172a45;
    --accent: #00ced1;
    --text-light: #e6f1ff;
    --text-dim: #8892b0;
    --silver: #d1d5db;
    --green-glow: #2ecc71;
    --red-border: #d63031;
    --gold-orange-border: #FFA500;
    --purple-glow: rgba(162, 89, 255, 0.9);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 120px;
}

body {
    margin: 0;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--navy);
    color: var(--text-light);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* ═════════════════════════════════════════════════════════════════════════════ */
/* HEADER STYLES */
/* ═════════════════════════════════════════════════════════════════════════════ */

header {
    background: var(--silver);
    background-image: linear-gradient(to bottom, #d1d5db, #bdc3c7);
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    height: 64px;
    border-bottom: 2px solid var(--accent);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
    font-weight: bold;
    font-size: 1.3rem;
    color: var(--navy) !important;
    transition: transform 0.3s ease;
    text-decoration: none;
}

.logo:hover {
    transform: scale(1.02);
}

.logo img {
    height: 42px;
    width: auto;
    border-radius: 12px;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.logo:hover img {
    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.25));
    transform: translateY(-1px);
}

/* Mobile menu button */
#mobile-menu-button {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    flex-shrink: 0;
    transition: transform 0.2s ease;
}

#mobile-menu-button:active {
    transform: scale(0.95);
}

#mobile-menu-button svg {
    width: 28px;
    height: 28px;
    stroke: var(--navy);
}

/* Navigation links */
.nav-links {
    display: flex;
    gap: 6px;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--navy);
    font-weight: 600;
    font-size: 0.78rem;
    transition: all 0.3s ease;
    position: relative;
    padding: 6px 10px;
    border-radius: 6px;
}

.nav-links a:hover {
    background: rgba(10, 25, 47, 0.06);
}

.nav-links a::after {
    display: none;
}

/* Divider between text links and buttons */
.nav-divider {
    width: 1px;
    height: 24px;
    background: rgba(10, 25, 47, 0.15);
    margin: 0 6px;
    flex-shrink: 0;
}

/* Navigation buttons */
.nav-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 5px 12px;
    border-radius: 6px;
    font-weight: 700;
    font-size: 0.7rem;
    letter-spacing: 0.02em;
    text-decoration: none !important;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.nav-btn:hover {
    background: rgba(10, 25, 47, 0.06) !important;
}

.nav-btn-educator {
    background: var(--navy);
    color: var(--accent) !important;
    border: 1.5px solid var(--accent);
}

.nav-btn-educator:hover {
    background: var(--accent) !important;
    color: var(--navy) !important;
}

.nav-btn-student {
    background: var(--accent);
    color: var(--navy) !important;
    border: 1.5px solid var(--accent);
}

.nav-btn-student:hover {
    background: transparent !important;
    color: var(--navy) !important;
}

.nav-btn-research {
    background: transparent;
    color: var(--navy) !important;
    border: 1.5px solid #4da3e8;
}

.nav-btn-research:hover {
    background: #4da3e8 !important;
    color: white !important;
}

.nav-btn-author {
    background: transparent;
    color: var(--navy) !important;
    border: 1.5px solid var(--gold-orange-border);
}

.nav-btn-author:hover {
    background: var(--gold-orange-border) !important;
    color: var(--navy) !important;
}

/* WorldConduit button */
.world-conduit-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 5px 14px;
    border-radius: 20px;
    font-weight: 700;
    font-size: 0.7rem;
    letter-spacing: 0.03em;
    text-decoration: none !important;
    border: 0px solid;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.world-conduit-btn svg {
    width: 14px;
    height: 14px;
    flex-shrink: 0;
}

/* Privacy banner */
.privacy-banner {
    background: rgba(0, 206, 209, 0.08);
    color: var(--text-dim);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    padding: 10px 20px;
    text-align: center;
    border-bottom: 1px solid rgba(0, 206, 209, 0.25);
    font-family: 'Courier New', monospace;
    font-weight: 500;
}

/* ═════════════════════════════════════════════════════════════════════════════ */
/* RESPONSIVE DESIGN */
/* ═════════════════════════════════════════════════════════════════════════════ */

@media (max-width: 1024px) {
    #mobile-menu-button {
        display: block;
    }

    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--silver);
        background-image: linear-gradient(to bottom, #d1d5db, #c8cdd2);
        padding: 8px 0;
        border-bottom: 2px solid var(--accent);
        box-shadow: 0 8px 20px rgba(0,0,0,0.15);
        gap: 0;
        align-items: stretch;
        z-index: 999;
    }

    .nav-links a {
        padding: 12px 24px;
        display: block;
        border-radius: 0;
        font-size: 0.85rem;
    }

    .nav-links a:hover {
        background: rgba(10, 25, 47, 0.04);
    }

    .nav-divider {
        width: auto;
        height: 1px;
        background: rgba(10, 25, 47, 0.08);
        margin: 6px 16px;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-btn {
        margin: 4px 16px;
        padding: 10px 16px;
        text-align: center;
        border-radius: 8px;
        font-size: 0.75rem;
    }

    .nav-links a.nav-btn {
        border-bottom: none;
    }
}

@media (max-width: 768px) {
    header {
        padding: 0 1rem;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 1.2rem;
    }

    .logo img {
        height: 45px;
    }

    .world-conduit-btn span {
        display: none;
    }

    .world-conduit-btn {
        padding: 5px 8px;
    }
}