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

:root {
    --bg: #f5f5f5;
    --fg: #111;
    --accent: #111;
    --border: #111;
    --radius: 14px;
    --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

html, body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--fg);
    font-family: var(--font);
    -webkit-font-smoothing: antialiased;
    overscroll-behavior: none;
    -webkit-tap-highlight-color: transparent;
}

body {
    min-height: 100dvh;
}

/* ===== Picker view ===== */
.picker {
    max-width: 560px;
    margin: 0 auto;
    padding: 24px 18px 40px;
}

.picker header h1 {
    font-size: clamp(2rem, 8vw, 3rem);
    font-weight: 900;
    letter-spacing: -0.03em;
    text-transform: lowercase;
    margin: 0 0 4px;
}
.picker header h1 span { opacity: 0.4; }
.picker header p {
    margin: 0 0 24px;
    opacity: 0.7;
    font-size: 1rem;
}

.presets {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin-bottom: 18px;
}
.presets button {
    appearance: none;
    border: 2px solid var(--border);
    background: var(--bg);
    color: var(--fg);
    font-family: inherit;
    font-weight: 900;
    font-size: clamp(0.95rem, 3.6vw, 1.1rem);
    letter-spacing: 0.02em;
    text-transform: uppercase;
    padding: 22px 10px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: transform 0.08s ease, background 0.15s ease, color 0.15s ease;
}
.presets button:active {
    transform: scale(0.97);
    background: var(--fg);
    color: var(--bg);
}

.custom {
    display: flex;
    gap: 8px;
    margin-bottom: 22px;
}
.custom input {
    flex: 1;
    min-width: 0;
    border: 2px solid var(--border);
    background: var(--bg);
    color: var(--fg);
    font-family: inherit;
    font-weight: 700;
    font-size: 1rem;
    padding: 14px 14px;
    border-radius: var(--radius);
    text-transform: uppercase;
}
.custom input:focus { outline: none; background: #fff; }
.custom button {
    appearance: none;
    border: 2px solid var(--border);
    background: var(--fg);
    color: var(--bg);
    font-family: inherit;
    font-weight: 900;
    font-size: 1rem;
    letter-spacing: 0.05em;
    padding: 0 22px;
    border-radius: var(--radius);
    cursor: pointer;
}
.custom button:active { transform: scale(0.97); }

.settings {
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 6px 14px;
    margin-bottom: 24px;
}
.settings summary {
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 10px 0;
    cursor: pointer;
    list-style: none;
}
.settings summary::-webkit-details-marker { display: none; }
.settings .row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 10px 0;
    border-top: 1px solid rgba(0,0,0,0.1);
}
.settings .row span { font-weight: 700; }
.settings input[type="range"] { flex: 1; max-width: 200px; }
.settings select {
    font-family: inherit;
    font-weight: 700;
    border: 2px solid var(--border);
    border-radius: 8px;
    padding: 6px 8px;
    background: var(--bg);
}
.settings output { font-variant-numeric: tabular-nums; min-width: 56px; text-align: right; }

.picker footer {
    text-align: center;
    opacity: 0.5;
}

/* ===== Display view (fullscreen message) ===== */
.display {
    display: none;
    position: fixed;
    inset: 0;
    background: #000;
    color: #fff;
    z-index: 10;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 4vmin;
    cursor: pointer;
    user-select: none;
    -webkit-user-select: none;
}
body.mode-display .display {
    display: flex;
}
body.mode-display .picker {
    display: none;
}

.display-text {
    font-family: var(--font);
    font-weight: 900;
    line-height: 0.95;
    letter-spacing: -0.02em;
    text-transform: uppercase;
    word-break: break-word;
    /* font-size is set by JS to fit viewport */
}

@keyframes flash-bw {
    0%, 49%   { background-color: #000; color: #fff; }
    50%, 100% { background-color: #fff; color: #000; }
}
@keyframes flash-yk {
    0%, 49%   { background-color: #000; color: #fee300; }
    50%, 100% { background-color: #fee300; color: #000; }
}
@keyframes flash-rw {
    0%, 49%   { background-color: #fff; color: #e10600; }
    50%, 100% { background-color: #e10600; color: #fff; }
}
@keyframes flash-gk {
    0%, 49%   { background-color: #000; color: #00ff66; }
    50%, 100% { background-color: #00ff66; color: #000; }
}
@keyframes flash-cm {
    0%, 49%   { background-color: #00e5ff; color: #ff00c8; }
    50%, 100% { background-color: #ff00c8; color: #00e5ff; }
}

body.mode-display.blink .display { animation: flash-bw 600ms steps(1) infinite; }
body.mode-display.blink[data-pair="bw"] .display { animation-name: flash-bw; }
body.mode-display.blink[data-pair="yk"] .display { animation-name: flash-yk; }
body.mode-display.blink[data-pair="rw"] .display { animation-name: flash-rw; }
body.mode-display.blink[data-pair="gk"] .display { animation-name: flash-gk; }
body.mode-display.blink[data-pair="cm"] .display { animation-name: flash-cm; }

/* Static (non-blink) color pairs */
body.mode-display[data-pair="bw"] .display { background: #000; color: #fff; }
body.mode-display[data-pair="yk"] .display { background: #000; color: #fee300; }
body.mode-display[data-pair="rw"] .display { background: #e10600; color: #fff; }
body.mode-display[data-pair="gk"] .display { background: #000; color: #00ff66; }
body.mode-display[data-pair="cm"] .display { background: #ff00c8; color: #00e5ff; }