/* Header/Nav Section */

/* ==============================================================
   HEADER / NAV — Frosted Glass 2.0
   ============================================================== */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: var(--z-nav);
    background: rgba(255, 255, 255, 0.78);
    backdrop-filter: saturate(200%) blur(28px);
    -webkit-backdrop-filter: saturate(200%) blur(28px);
    border-bottom: 1px solid rgba(90, 79, 243, 0.08);
    transition:
        padding 0.35s cubic-bezier(0.4, 0, 0.2, 1),
        background 0.35s,
        box-shadow 0.35s,
        border-color 0.35s,
        transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Prismatic top accent line */
header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-gradient-wide);
    opacity: 0;
    transition: opacity 0.4s;
}

header.scrolled::before {
    opacity: 1;
}

header.scrolled {
    background: rgba(255, 255, 255, 0.92);
    box-shadow: 0 1px 0 rgba(90, 79, 243, 0.08), 0 4px 20px rgba(0, 0, 0, 0.06);
    border-bottom-color: rgba(90, 79, 243, 0.06);
}

header.header--hidden {
    transform: translateY(-100%);
    pointer-events: none;
}

header.header--visible {
    transform: translateY(0);
    pointer-events: auto;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 5%;
    max-width: 1440px;
    margin: 0 auto;
    gap: 1rem;
    transition: padding 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

header.scrolled .header-inner {
    padding-top: 0.5rem;
    padding-bottom: 0.5rem;
}

/* --- Logo --- */
.logo {
    display: flex;
    align-items: center;
    flex-shrink: 0;
    transition: transform var(--transition-bounce), filter var(--transition-smooth);
    position: relative;
}

.logo:hover {
    transform: scale(1.03) translateY(-1px);
    filter: drop-shadow(0 4px 12px rgba(90, 79, 243, 0.25));
}

.logo img {
    height: 34px;
    width: auto;
    display: block;
}

/* --- Desktop Nav --- */
.nav-menu {
    display: flex;
    align-items: center;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    transition: color var(--transition-fast), transform var(--transition-bounce);
    position: relative;
    white-space: nowrap;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    letter-spacing: -0.01em;
}

/* Animated underline */
.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: var(--radius-pill);
}

.nav-links a:hover {
    color: var(--accent-primary);
    transform: translateY(-1px);
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-links a.active {
    color: var(--accent-primary);
    font-weight: 600;
}

.nav-links a.active::after {
    width: 100%;
}

/* --- Header Right --- */
.header-right {
    display: flex;
    gap: 0.55rem;
    align-items: center;
    flex-shrink: 0;
}

/* --- Dark Toggle --- */
.dark-toggle {
    background: none;
    border: 1.5px solid var(--border-color);
    color: var(--text-secondary);
    width: 38px;
    height: 38px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-smooth);
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
}

.dark-toggle:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: rgba(90, 79, 243, 0.07);
    transform: rotate(15deg) scale(1.08);
    box-shadow: 0 0 12px rgba(90, 79, 243, 0.15);
}

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

[data-theme="dark"] .dark-toggle .icon-sun {
    display: inline;
}

[data-theme="light"] .dark-toggle .icon-moon,
:root:not([data-theme]) .dark-toggle .icon-moon {
    display: inline;
}

/* --- Login / Sign Up Buttons --- */
.btn-login {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    border: 1.5px solid var(--border-accent);
    color: var(--accent-primary);
    padding: 0.52rem 1.3rem;
    border-radius: var(--radius-pill);
    font-size: 0.875rem;
    font-weight: 600;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    white-space: nowrap;
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

/* Shimmer sweep on login button */
.btn-login::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 60%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
    transform: skewX(-20deg);
    transition: left 0.5s ease;
}

.btn-login:hover::before {
    left: 150%;
}

.btn-login:hover {
    background: var(--accent-gradient);
    color: white;
    border-color: transparent;
    box-shadow: var(--shadow-glow);
    transform: translateY(-1px);
}

/* Pulse glow keyframe */
@keyframes pulse-glow {
    0%   { box-shadow: 0 0 0 0 rgba(90, 79, 243, 0.4); }
    70%  { box-shadow: 0 0 0 10px rgba(90, 79, 243, 0); }
    100% { box-shadow: 0 0 0 0 rgba(90, 79, 243, 0); }
}

.btn-pulse {
    animation: pulse-glow 2.2s infinite;
}

.btn-pulse:hover {
    animation: none;
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

/* --- Hamburger Toggle --- */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    width: 42px;
    height: 42px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
    flex-shrink: 0;
}

.nav-toggle:hover {
    background: rgba(90, 79, 243, 0.07);
}

.hamburger-line {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-primary);
    border-radius: var(--radius-pill);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: center;
}

.nav-toggle.active .hamburger-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-toggle.active .hamburger-line:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.nav-toggle.active .hamburger-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* --- Mobile Backdrop --- */
.nav-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(10, 8, 32, 0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}

.nav-backdrop.active {
    opacity: 1;
    visibility: visible;
}