@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;600;700;800&display=swap');

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg:           #06070e;
    --surface:      #0c0f1a;
    --card:         #0f1323;
    --border:       rgba(255, 255, 255, 0.06);
    --border-blue:  rgba(56, 189, 248, 0.20);
    --blue:         #38bdf8;
    --blue-dim:     rgba(56, 189, 248, 0.08);
    --text:         #e8edf5;
    --muted:        #7c8a9e;
    --tile-off:     #111111;
    --tile-on:      #ffffff;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

/* ── Navbar ── */
.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2.5rem;
    height: 60px;
    background: rgba(6, 7, 14, 0.82);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand {
    font-weight: 700;
    font-size: 0.88rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text);
    text-decoration: none;
}

.nav-tabs {
    display: flex;
    gap: 0.15rem;
}

.nav-tab {
    color: var(--muted);
    text-decoration: none;
    padding: 0.38rem 0.9rem;
    border-radius: 5px;
    font-size: 0.84rem;
    font-weight: 500;
    transition: color 0.12s, background 0.12s;
}

.nav-tab:hover {
    color: var(--text);
    background: rgba(255, 255, 255, 0.04);
}

.nav-tab.active {
    color: var(--blue);
    background: var(--blue-dim);
}

/* ── Shared button base ── */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.55rem 1.3rem;
    border-radius: 6px;
    font-size: 0.86rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    border: 1px solid var(--border-blue);
    background: transparent;
    color: var(--text);
    font-family: inherit;
    transition: background 0.12s, border-color 0.12s, color 0.12s;
}

.btn:hover {
    background: var(--blue-dim);
    border-color: var(--blue);
}

.btn-primary {
    background: var(--blue);
    color: #06070e;
    border-color: var(--blue);
    font-weight: 600;
}

.btn-primary:hover {
    background: #7dd3fc;
    border-color: #7dd3fc;
    color: #06070e;
}

/* ── Landing: Hero ── */
.hero {
    max-width: 720px;
    margin: 0 auto;
    padding: 6rem 1.5rem 2.8rem;
    text-align: center;
}

.badge {
    display: inline-block;
    padding: 0.28rem 0.85rem;
    background: var(--blue-dim);
    border: 1px solid var(--border-blue);
    border-radius: 999px;
    font-size: 0.71rem;
    font-weight: 600;
    color: var(--blue);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    margin-bottom: 1.6rem;
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 800;
    line-height: 1.12;
    letter-spacing: -0.03em;
    color: var(--text);
    margin-bottom: 3.67rem;
}

.hero-body {
    color: var(--muted);
    font-size: 0.97rem;
    line-height: 1.8;
    margin-bottom: 0.7rem;
    max-width: 580px;
    margin-left: auto;
    margin-right: auto;
}

.hero-body.lead {
    color: #aab4c4;
    font-size: 1.02rem;
    margin-bottom: 3.67rem;
}

.hero-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    margin-top: 2.25rem;
    flex-wrap: wrap;
}

/* ── Landing: Stages section ── */
.stages-section {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 1.5rem 5rem;
}

.section-rule {
    border: none;
    border-top: 1px solid var(--border);
    margin-bottom: 3rem;
}

.section-label {
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--blue);
    margin-bottom: 1.25rem;
}

.stages-overview {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.stage-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-top: 2px solid var(--blue);
    border-radius: 8px;
    padding: 1.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
}

.stage-num {
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    color: var(--blue);
    text-transform: uppercase;
}

.stage-card h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
}

.stage-card p {
    color: var(--muted);
    font-size: 0.86rem;
    line-height: 1.65;
    flex: 1;
}

/* ── Stage pages ── */
.stage-main {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 3rem 1.5rem;
    gap: 1rem;
}

.stage-main h1 {
    font-size: 1.6rem;
    font-weight: 700;
}

.stage-desc {
    color: var(--muted);
    font-size: 0.95rem;
}

/* ── Stage layout: grid box + side panel ── */
.stage-layout {
    display: flex;
    align-items: flex-end;
    gap: 1rem;
    margin-top: 1.5rem;
}

.stage-layout .box {
    margin-top: 0;
}

.side-menu {
    padding: 1.25rem 1rem;
    justify-content: flex-start;
}

/* ── Box (stage canvases) ── */
.box {
    background: #13182c;
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

/* ── 3×3 Grid ── */
.grid {
    display: grid;
    grid-template-columns: repeat(3, 60px);
    grid-template-rows: repeat(3, 60px);
    border: 1px solid var(--border-blue);
}

.tile {
    width: 60px;
    height: 60px;
    background: var(--tile-off);
    border: 1px solid var(--border-blue);
    cursor: pointer;
    transition: background 0.1s;
}

.tile:not(.on):hover {
    background: #222222;
}

.tile.on {
    background: var(--tile-on);
}

/* ── Recognize button ── */
.recognize-btn {
    font-size: 0.92rem;
    padding: 0.6rem 2rem;
    letter-spacing: 0.02em;
}

/* ── Refresh button ── */
.refresh-btn {
    font-size: 0.92rem;
    padding: 0.6rem 2rem;
    letter-spacing: 0.02em;
    border: none;
}

.refresh-btn:hover {
    border: none;
}

/* ── Standalone result box ── */
.result-box {
    min-width: 260px;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.1rem 1.6rem;
    font-size: 0.95rem;
    color: var(--muted);
    line-height: 1.9;
    visibility: hidden;
}

.result-box:not(:empty) {
    visibility: visible;
}

.result-row {
    color: var(--text);
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.02em;
}

/* ── Stage 3 draw canvas ── */
.draw-canvas {
    display: block;
    border-radius: 4px;
    cursor: crosshair;
    touch-action: none;
}