/* ── Shimmer animation ───────────────────────────────────── */
@keyframes shimmer {
    0%   { background-position: -200% center; }
    100% { background-position:  200% center; }
}


/* ── h1 neon flicker ─────────────────────────────────────── */
@keyframes neon-flicker {
    0%,  92%         { opacity: 1; filter: none; }
    93%              { opacity: 0.7; filter: brightness(1.8) drop-shadow(0 0 6px var(--color-accent)); }
    93.5%            { opacity: 1; filter: none; }
    94.5%            { opacity: 0.4; filter: brightness(2.5) drop-shadow(0 0 12px var(--color-accent)); }
    95%              { opacity: 1; filter: brightness(1.4) drop-shadow(0 0 8px var(--color-accent)); }
    96%              { opacity: 0.85; filter: none; }
    96.5%            { opacity: 1; filter: brightness(1.2) drop-shadow(0 0 4px var(--color-accent)); }
    100%             { opacity: 1; filter: none; }
}

header {
    background: var(--color-glass);
    backdrop-filter: var(--blur-glass);
    -webkit-backdrop-filter: var(--blur-glass);
    border-bottom: 1px solid var(--color-glass-border);
    color: var(--color-text);
    font-family: var(--font-condensed);
    padding: 1.5em 1em 1.25em;
    position: relative;
    text-align: center;
}

/* ── h1 wrapper: positions glitch slice clones ───────────── */
.h1-wrapper {
    position: relative;
    display: inline-block;
}

/* Each clone sits exactly over the real h1 */
.h1-slice {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    white-space: nowrap;
    pointer-events: none;
    margin: 0;
    padding: 0;
    animation: none;
    /* Duplicate the exact same gradient as header h1 */
    font-size: 3.5em;
    font-family: var(--font-condensed);
    letter-spacing: 0.02em;
    background: linear-gradient(
        90deg,
        var(--color-text) 0%,
        var(--color-text) 40%,
        var(--color-accent) 60%,
        var(--color-text) 75%,
        var(--color-text) 100%
    );
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Chromatic aberration ghost clones */
.h1-slice--red {
    -webkit-text-fill-color: rgba(255, 0, 60, 0.55);
    color: rgba(255, 0, 60, 0.55);
    background: none;
}

.h1-slice--cyan {
    -webkit-text-fill-color: rgba(0, 255, 220, 0.45);
    color: rgba(0, 255, 220, 0.45);
    background: none;
}

@media screen and (max-width: 56em) { .h1-slice { font-size: 2.75em; } }
@media screen and (max-width: 48em) { .h1-slice { font-size: 2.25em; } }
@media screen and (max-width: 32em) { .h1-slice { font-size: 1.75em; } }

header h1 {
    animation: shimmer 6s linear infinite, neon-flicker 9s linear infinite;
    font-size: 3.5em;
    letter-spacing: 0.02em;
    background: linear-gradient(
        90deg,
        var(--color-text) 0%,
        var(--color-text) 40%,
        var(--color-accent) 60%,
        var(--color-text) 75%,
        var(--color-text) 100%
    );
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}



/* Fallback for browsers without background-clip: text */
@supports not (-webkit-background-clip: text) {
    header h1 {
        color: var(--color-text);
        background: none;
        animation: none;
    }
}

@media (prefers-reduced-motion: reduce) {
    header h1 {
        animation: none;
    }
}

.glitch-disabled header h1 {
    animation: shimmer 6s linear infinite;
}

header h2 {
    font-size: 1.1em;
    color: var(--color-text-muted);
    font-family: var(--font-condensed);
    letter-spacing: 0.18em;
    margin-top: 0.5em;
    text-transform: uppercase;
}

/* ── Header button group ─────────────────────────────────── */
.header-buttons {
    display: flex;
    align-items: center;
    gap: 0.4em;
    position: absolute;
    right: 1em;
    top: 1em;
}

/* Anchor tooltip to the right edge so it doesn't overflow off-screen */
.header-buttons [data-tooltip]::after {
    left: auto;
    right: 0;
    transform: translateY(-4px);
}

.header-buttons [data-tooltip]:hover::after,
.header-buttons [data-tooltip]:focus-visible::after {
    transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
    .header-buttons [data-tooltip]::after {
        transform: translateY(0);
    }
}

/* ── Shared header button style ──────────────────────────── */
.header-buttons button {
    background: var(--color-glass);
    backdrop-filter: var(--blur-glass);
    border: 1px solid var(--color-glass-border);
    border-radius: var(--radius-btn);
    color: var(--color-text-muted);
    cursor: pointer;
    font-size: 1em;
    line-height: 1;
    padding: 0.4em 0.55em;
    transition: var(--transition-glow);
    display: flex;
    align-items: center;
    justify-content: center;
}

.header-buttons button:hover {
    border-color: var(--color-accent-dim);
    color: var(--color-accent);
    box-shadow: 0 0 10px var(--color-accent-glow);
}

.header-buttons button svg {
    display: block;
    height: 1.1em;
    width: 1.1em;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* ── Glitch toggle ───────────────────────────────────────── */
.glitch-off-line {
    display: none;
}

#glitch-toggle[aria-pressed="true"] .glitch-off-line {
    display: block;
}

#glitch-toggle[aria-pressed="true"] {
    color: var(--color-text-muted);
    opacity: 0.5;
}

/* ── Sun/moon visibility ─────────────────────────────────── */
.icon-sun  { display: none; }
.icon-moon { display: flex; }

[data-theme="light"] .icon-sun  { display: flex; }
[data-theme="light"] .icon-moon { display: none; }

/* ── Light mode: stronger button contrast ────────────────── */
[data-theme="light"] .header-buttons button {
    border-color: var(--color-border-btn);
    color: var(--color-text-muted);
}

[data-theme="light"] .header-buttons button:hover {
    border-color: var(--color-accent-dim);
    color: var(--color-accent);
}

/* ── Responsive ──────────────────────────────────────────── */
@media screen and (max-width: 56em) {
    header h1 { font-size: 2.75em; }
}

@media screen and (max-width: 48em) {
    header h1 { font-size: 2.25em; }
}

@media screen and (max-width: 32em) {
    header h1 { font-size: 1.75em; }
    header h2 { font-size: 0.9em; }
}