/* ── Reset & tokens ─────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg:        #080c14;
    --bg2:       #0d1322;
    --bg3:       #121929;
    --border:    #1e2d4a;
    --primary:   #3b82f6;
    --primary-d: #1d4ed8;
    --accent:    #f59e0b;
    --accent2:   #10b981;
    --danger:    #ef4444;
    --txt:       #e2e8f0;
    --txt2:      #94a3b8;
    --txt3: #ffffff;
    --radius:    10px;
    --shadow:    0 4px 24px rgba(0,0,0,.5);

    --mercury: #a8a8a8;
    --venus:   #ffc649;
    --earth:   #6495ed;
    --mars:    #cd5c5c;
    --jupiter: #ff8c00;
    --saturn:  #ffd700;
    --uranus:  #40e0d0;
    --neptune: #1e90ff;
    --pluto:   #8b6355;

    font-family: 'Syne', sans-serif;
    font-size: 14px;
    color: var(--txt);
    background: var(--bg);
}

/* ── Scrollbar ──────────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* ── Header ─────────────────────────────────────────────────────────────────── */
header {
    border-bottom: 1px solid var(--border);
    padding: 0 24px;
    height: 60px;
    display: flex;
    align-items: center;
    background: linear-gradient(90deg, #0a1020, #0d1830 60%, #0a1020);
    position: sticky; top: 0; z-index: 50;
    backdrop-filter: blur(10px);
}
.header-inner { display: flex; align-items: center; gap: 20px; width: 100%; }
.logo {
    font-size: 1.4rem; font-weight: 800; letter-spacing: -0.5px;
    display: flex; align-items: center; gap: 10px;
}
.logo em { color: var(--primary); font-style: normal; }
.logo-icon { color: var(--accent); font-size: 1.2rem; }
.tagline { font-size: .8rem; color: var(--txt3); margin-left: auto; font-family: 'Space Mono', monospace; }

/* ── Layout ─────────────────────────────────────────────────────────────────── */
main {
    display: grid;
    grid-template-columns: 300px 1fr 320px;
    height: calc(100vh - 60px - 36px);
    overflow: hidden;
}

/* ── Panels ─────────────────────────────────────────────────────────────────── */
.panel {
    border-right: 1px solid var(--border);
    overflow-y: auto;
    padding: 18px;
}
.panel-controls { background: var(--bg2); }
.panel-sim      { background: var(--bg);  display: flex; flex-direction: column; padding: 0; border-right: 1px solid var(--border); }
.panel-results  { background: var(--bg2); border-right: none; }

/* ── Control sections ───────────────────────────────────────────────────────── */
.ctrl-section { margin-bottom: 22px; }
.ctrl-label {
    display: flex; align-items: center; gap: 7px;
    font-size: .7rem; font-weight: 600; letter-spacing: .1em;
    text-transform: uppercase; color: var(--txt3);
    margin-bottom: 10px;
}


/* Mass input */
.mass-row { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.mass-row input {
    flex: 1; background: var(--bg3); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 9px 12px;
    color: var(--txt); font-family: 'Space Mono', monospace;
    font-size: 1rem; outline: none; transition: border .2s;
}
.mass-row input:focus { border-color: var(--primary); }
.unit-badge {
    background: var(--bg3); border: 1px solid var(--border);
    padding: 9px 12px; border-radius: var(--radius);
    color: var(--txt3); font-family: 'Space Mono', monospace;
}
.mass-presets { display: flex; flex-wrap: wrap; gap: 5px; }
.preset-btn {
    background: var(--bg3); border: 1px solid var(--border);
    color: var(--txt2); padding: 4px 9px; border-radius: 6px;
    cursor: pointer; font-size: .75rem; transition: all .15s;
}
.preset-btn:hover { border-color: var(--primary); color: var(--primary); }

/* Height buttons */
.height-btns, .shape-btns { display: flex; flex-wrap: wrap; gap: 6px; }
.height-btn, .shape-btn {
    background: var(--bg3); border: 1px solid var(--border);
    color: var(--txt2); padding: 7px 13px; border-radius: 8px;
    cursor: pointer; font-family: 'Syne', sans-serif;
    font-size: .82rem; transition: all .15s;
}
.height-btn:hover, .shape-btn:hover { border-color: var(--primary); color: var(--txt); }
.height-btn.active, .shape-btn.active {
    background: var(--primary); border-color: var(--primary);
    color: #fff; font-weight: 600;
}
.shape-btn { display: flex; align-items: center; gap: 6px; width: 100%; }
.shape-btn em { margin-left: auto; font-style: normal; font-size: .7rem; color: var(--txt3); font-family: 'Space Mono', monospace; }
.shape-btn.active em { color: #bfdbfe; }

/* Icon search */
.icon-search-row {
    display: flex; align-items: center; gap: 8px;
    background: var(--bg3); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 8px 12px; margin-bottom: 10px;
}
.icon-search-row i { color: var(--txt3); }
.icon-search-row input {
    flex: 1; background: transparent; border: none;
    color: var(--txt); outline: none; font-family: 'Syne', sans-serif;
    font-size: .9rem;
}
.icon-grid {
    display: grid; grid-template-columns: repeat(6, 1fr);
    gap: 4px; max-height: 160px; overflow-y: auto;
}
.icon-item {
    display: flex; flex-direction: column; align-items: center;
    justify-content: center; gap: 3px;
    padding: 6px 2px; border-radius: 7px;
    border: 1px solid transparent; cursor: pointer;
    transition: all .15s; font-size: .6rem; color: var(--txt3);
}
.icon-item i { font-size: 1.1rem; color: var(--txt2); }
.icon-item:hover { background: var(--bg3); border-color: var(--border); color: var(--txt); }
.icon-item:hover i { color: var(--primary); }
.icon-item.selected { background: #1e3a5f; border-color: var(--primary); }
.icon-item.selected i { color: var(--primary); }

.selected-icon-row {
    display: flex; align-items: center; gap: 8px;
    margin-top: 8px; font-size: .82rem; color: var(--txt2);
}
.selected-icon-row i { color: var(--primary); font-size: 1rem; }
#clear-icon-btn {
    margin-left: auto; background: none; border: none;
    color: var(--txt3); cursor: pointer; font-size: .9rem;
    padding: 2px 5px;
}
#clear-icon-btn:hover { color: var(--danger); }

/* Run button */
.run-btn {
    width: 100%; padding: 13px;
    background: linear-gradient(135deg, var(--primary), var(--primary-d));
    border: none; border-radius: var(--radius);
    color: #fff; font-family: 'Syne', sans-serif;
    font-size: 1rem; font-weight: 700; letter-spacing: .05em;
    cursor: pointer; transition: all .2s;
    box-shadow: 0 4px 16px rgba(59,130,246,.3);
    display: flex; align-items: center; justify-content: center; gap: 9px;
}
.run-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 24px rgba(59,130,246,.45); }
.run-btn:active { transform: translateY(0); }
.run-btn.loading { opacity: .7; pointer-events: none; }

/* ── Simulation stage ───────────────────────────────────────────────────────── */
.sim-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 12px 18px; border-bottom: 1px solid var(--border);
    background: var(--bg2);
}
.sim-title { font-size: .82rem; color: var(--txt2); font-family: 'Space Mono', monospace; }
.sim-controls { display: flex; gap: 6px; }
.icon-ctrl-btn {
    background: var(--bg3); border: 1px solid var(--border);
    color: var(--txt2); width: 32px; height: 32px; border-radius: 7px;
    cursor: pointer; transition: all .15s; font-size: .9rem;
}
.icon-ctrl-btn:hover:not(:disabled) { border-color: var(--primary); color: var(--primary); }
.icon-ctrl-btn:disabled { opacity: .35; cursor: default; }

.sim-stage {
    flex: 1; position: relative; overflow: hidden;
    background: radial-gradient(ellipse at 50% 0%, #0d1f3c 0%, var(--bg) 70%);
}
.sim-placeholder {
    position: absolute; inset: 0;
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    gap: 16px; color: var(--txt3);
}
.sim-placeholder i { font-size: 2.5rem; color: var(--border); }
.sim-placeholder p { text-align: center; line-height: 1.6; font-size: .9rem; }

/* Planet column inside canvas */
.planet-col {
    position: absolute; top: 0; bottom: 0;
    display: flex; flex-direction: column; align-items: center;
}
.planet-label {
    font-size: .62rem; font-weight: 700; letter-spacing: .05em;
    text-transform: uppercase; padding-top: 6px;
    font-family: 'Space Mono', monospace;
}
.planet-track {
    flex: 1; width: 2px; opacity: .25; margin: 4px 0;
    background: repeating-linear-gradient(
            to bottom, currentColor 0, currentColor 4px, transparent 4px, transparent 10px
    );
}
.planet-ground {
    font-size: .58rem; padding-bottom: 4px; opacity: .6;
    font-family: 'Space Mono', monospace;
}
.falling-object {
    position: absolute; transform: translate(-50%, -50%);
    transition: color .3s;
    filter: drop-shadow(0 0 6px currentColor);
    pointer-events: none;
}
.falling-object i { font-size: 1.2rem; }
.trail-dot {
    position: absolute; width: 3px; height: 3px;
    border-radius: 50%; transform: translate(-50%, -50%);
    opacity: .35; pointer-events: none;
}
.impact-flash {
    position: absolute; transform: translate(-50%, -50%);
    border-radius: 50%; pointer-events: none;
    animation: flash .5s ease-out forwards;
}
@keyframes flash {
    0%   { width: 4px; height: 4px; opacity: .9; }
    100% { width: 40px; height: 40px; opacity: 0; }
}

/* Ground line */
.ground-line {
    position: absolute; left: 0; right: 0; height: 2px;
    background: linear-gradient(90deg, transparent, var(--border) 20%, var(--border) 80%, transparent);
}
.ground-label {
    position: absolute; right: 8px; font-size: .65rem;
    color: var(--txt3); font-family: 'Space Mono', monospace;
}

.speed-legend {
    display: flex; gap: 16px; padding: 8px 18px;
    border-top: 1px solid var(--border); background: var(--bg2);
    font-size: .72rem; color: var(--txt3);
}
.speed-legend span { display: flex; align-items: center; gap: 5px; }

/* ── Results panel ──────────────────────────────────────────────────────────── */
.results-header {
    display: flex; align-items: center; justify-content: space-between;
    margin-bottom: 14px;
}
.results-header h2 {
    font-size: .95rem; font-weight: 700;
    display: flex; align-items: center; gap: 7px;
}
.results-header h2 i { color: var(--primary); }
#sort-select {
    background: var(--bg3); border: 1px solid var(--border);
    color: var(--txt2); padding: 5px 8px; border-radius: 7px;
    font-family: 'Syne', sans-serif; font-size: .75rem; outline: none;
}

.results-empty {
    display: flex; flex-direction: column; align-items: center;
    justify-content: center; gap: 12px; height: 200px;
    color: var(--txt3);
}
.results-empty i { font-size: 2rem; }

.result-card {
    background: var(--bg3); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 12px 14px;
    margin-bottom: 8px; transition: border-color .2s;
    cursor: default;
}
.result-card:hover { border-color: var(--border); }
.result-card.landed { border-left: 3px solid var(--accent2); }

.card-header {
    display: flex; align-items: center; gap: 8px; margin-bottom: 8px;
}
.planet-dot {
    width: 10px; height: 10px; border-radius: 50%; flex-shrink: 0;
}
.card-planet { font-weight: 700; font-size: .9rem; flex: 1; }
.card-gravity {
    font-size: .72rem; color: var(--txt3);
    font-family: 'Space Mono', monospace;
}
.card-impact-badge {
    font-size: .65rem; padding: 2px 7px; border-radius: 4px;
    background: #1a2a40; color: var(--accent);
}

.card-metrics {
    display: grid; grid-template-columns: 1fr 1fr;
    gap: 5px 10px;
}
.metric { display: flex; flex-direction: column; gap: 1px; }
.metric-label {
    font-size: .62rem; color: var(--txt3); text-transform: uppercase;
    letter-spacing: .06em;
}
.metric-value {
    font-size: .82rem; font-family: 'Space Mono', monospace; color: var(--txt);
}
.metric-value.highlight { color: var(--accent); }

.progress-bar {
    height: 3px; background: var(--bg2); border-radius: 2px;
    margin-top: 8px; overflow: hidden;
}
.progress-fill {
    height: 100%; border-radius: 2px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transition: width .3s;
}

/* ── Footer ─────────────────────────────────────────────────────────────────── */
footer {
    height: 36px; border-top: 1px solid var(--border);
    display: flex; align-items: center; justify-content: space-between;
    padding: 0 24px; background: var(--bg2);
    font-size: .7rem; color: var(--txt3);
}
footer a { color: var(--primary); text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* ── Animations ─────────────────────────────────────────────────────────────── */
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: translateY(0); } }
.result-card { animation: fadeIn .25s ease both; }

/* ── Responsive ─────────────────────────────────────────────────────────────── */
@media (max-width: 1100px) {
    main { grid-template-columns: 260px 1fr 280px; }
}
@media (max-width: 860px) {
    main { grid-template-columns: 1fr; grid-template-rows: auto 400px auto; height: auto; overflow: visible; }
    .panel { max-height: none; overflow: visible; }
    .panel-sim { height: 400px; }
}