/* ============================================================
   RC CAR BLE CONTROLLER — style.css
   ============================================================ */

/* ---------- RESET & BASE ---------- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg:          #0d0f14;
    --surface:     #161b27;
    --surface2:    #1e2535;
    --blue:        #2979ff;
    --blue-glow:   #2979ffaa;
    --blue-dark:   #1a4fb5;
    --blue-light:  #5b9aff;
    --red:         #ff3d3d;
    --red-glow:    #ff3d3d99;
    --green:       #00e676;
    --yellow:      #ffd740;
    --text:        #e8eaf6;
    --text-dim:    #7986a8;
    --radius-lg:   18px;
    --radius-md:   12px;
    --radius-sm:   8px;
    --font:        "Segoe UI", system-ui, sans-serif;
    --transition:  0.15s ease;
}

html, body {
    height: 100%;
    background: var(--bg);
    color: var(--text);
    font-family: var(--font);
    -webkit-tap-highlight-color: transparent;
    user-select: none;
    overflow-x: hidden;
}

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 16px 12px 32px;
    min-height: 100vh;
    gap: 16px;
}

/* ---------- HEADER ---------- */
.header {
    width: 100%;
    max-width: 540px;
    text-align: center;
}

.app-logo {
    font-size: 3.5rem;
    line-height: 1;
    margin-bottom: 6px;
    animation: logo-float 3s ease-in-out infinite;
    display: block;
}

@keyframes logo-float {
    0%, 100% { transform: translateY(0);    }
    50%       { transform: translateY(-6px); }
}

.header h1 {
    font-size: clamp(2rem, 9vw, 3.2rem);
    font-weight: 900;
    letter-spacing: 0.28em;
    text-transform: uppercase;
    background: linear-gradient(135deg, #ffffff 0%, var(--blue-light) 40%, var(--blue) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 4px;
    filter: drop-shadow(0 0 18px var(--blue-glow));
}

.header .subtitle {
    font-size: 0.78rem;
    color: var(--text-dim);
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

/* ---------- STATUS BADGE ---------- */
.status-badge {
    display: inline-block;
    padding: 4px 14px;
    border-radius: 100px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-top: 8px;
    transition: background var(--transition), color var(--transition);
}

.status-badge.disconnected {
    background: #1e2535;
    color: var(--text-dim);
    border: 1px solid #2a3356;
}

.status-badge.scanning {
    background: #241f00;
    color: var(--yellow);
    border: 1px solid var(--yellow);
    animation: pulse-badge 0.8s ease-in-out infinite alternate;
}

.status-badge.connected {
    background: #002914;
    color: var(--green);
    border: 1px solid var(--green);
}

@keyframes pulse-badge {
    from { opacity: 0.7; }
    to   { opacity: 1.0; }
}

/* ---------- CONNECT BUTTON ---------- */
.connect-btn {
    width: 100%;
    max-width: 540px;
    padding: 16px;
    border: none;
    border-radius: var(--radius-lg);
    background: linear-gradient(135deg, var(--blue) 0%, var(--blue-dark) 100%);
    color: #fff;
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    cursor: pointer;
    box-shadow: 0 4px 24px var(--blue-glow);
    transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
}

.connect-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px var(--blue-glow);
}

.connect-btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 12px var(--blue-glow);
}

/* ---------- CARD ---------- */
.card {
    width: 100%;
    max-width: 540px;
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 20px;
    border: 1px solid #1e2a45;
}

.card-title {
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-dim);
    margin-bottom: 14px;
}


/* ---------- CONTROL PAD ---------- */
.control-pad {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    grid-template-rows: auto auto auto;
    gap: 10px;
    width: 100%;
    max-width: 340px;
    margin: 0 auto;
}

/* Grid placement */
#btnForward { grid-column: 2; grid-row: 1; }
#btnLeft    { grid-column: 1; grid-row: 2; }
#btnStop    { grid-column: 2; grid-row: 2; }
#btnRight   { grid-column: 3; grid-row: 2; }
#btnReverse { grid-column: 2; grid-row: 3; }

/* ---------- CONTROL BUTTONS ---------- */
.ctrl-btn {
    aspect-ratio: 1 / 1;
    border: none;
    border-radius: var(--radius-lg);
    background: var(--surface2);
    color: var(--text);
    font-size: 1.6rem;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    border: 1.5px solid #2a3356;
    transition: background var(--transition),
                box-shadow var(--transition),
                transform var(--transition),
                border-color var(--transition);
    touch-action: none;
    -webkit-touch-callout: none;
}

.ctrl-btn .btn-label {
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-dim);
}

.ctrl-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    pointer-events: none;
}

.ctrl-btn:not(:disabled):hover {
    background: var(--surface2);
    border-color: var(--blue);
    box-shadow: 0 0 16px var(--blue-glow);
    transform: scale(1.04);
}

.ctrl-btn:not(:disabled):active,
.ctrl-btn.active-btn {
    background: var(--blue);
    border-color: var(--blue-light);
    box-shadow: 0 0 24px var(--blue-glow);
    transform: scale(0.96);
    color: #fff;
}

/* STOP button overrides */
#btnStop {
    background: #1c0a0a;
    border-color: #5a1010;
    font-size: 0.9rem;
    font-weight: 800;
    letter-spacing: 0.06em;
}

#btnStop:not(:disabled):hover {
    background: #2a0e0e;
    border-color: var(--red);
    box-shadow: 0 0 20px var(--red-glow);
}

#btnStop:not(:disabled):active,
#btnStop.active-btn {
    background: var(--red);
    border-color: #ff6b6b;
    box-shadow: 0 0 28px var(--red-glow);
}

/* ---------- ERROR LOG ---------- */
.error-log {
    width: 100%;
    max-width: 540px;
    min-height: 24px;
    font-size: 0.78rem;
    color: var(--red);
    text-align: center;
    font-weight: 600;
    letter-spacing: 0.02em;
}

/* ---------- DEBUG PANEL ---------- */
.debug-section {
    width: 100%;
    max-width: 540px;
    border: 1px solid #1e2a45;
    border-radius: var(--radius-md);
    overflow: hidden;
}

.debug-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 16px;
    background: var(--surface);
    cursor: pointer;
    border: none;
    color: var(--text-dim);
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    width: 100%;
    text-align: left;
    transition: background var(--transition);
}

.debug-toggle:hover {
    background: var(--surface2);
    color: var(--text);
}

.debug-panel {
    display: none;
    padding: 14px 16px;
    background: #0b0e18;
    border-top: 1px solid #1e2a45;
}

.debug-panel.open {
    display: block;
}

.debug-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.75rem;
    font-family: "Consolas", "Courier New", monospace;
}

.debug-table tr + tr td {
    padding-top: 6px;
}

.debug-table td:first-child {
    color: var(--text-dim);
    padding-right: 12px;
    white-space: nowrap;
    width: 1%;
    vertical-align: top;
}

.debug-table td:last-child {
    color: var(--blue-light);
    word-break: break-all;
}

/* special colours for status cells */
.debug-table td.status-ok   { color: var(--green);  }
.debug-table td.status-err  { color: var(--red);    }
.debug-table td.status-warn { color: var(--yellow); }

/* ---------- KEYBOARD HINT ---------- */
.key-hint {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    justify-content: center;
    margin-top: 4px;
}

.key-hint kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 3px 8px;
    background: var(--surface2);
    border: 1px solid #2a3356;
    border-radius: 6px;
    font-size: 0.72rem;
    font-family: var(--font);
    color: var(--text-dim);
    min-width: 28px;
}

/* ---------- SCROLLBAR ---------- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: #2a3356; border-radius: 3px; }

/* ============================================================
   RESPONSIVE — mobile-first
   xs : < 380px    small phones
   sm : 380–479px  regular phones  (base styles target this)
   md : 480–599px  large phones
   lg : 600–899px  tablet portrait
   xl : 900px+     tablet landscape / small desktop
   ============================================================ */

/* xs — very small phones */
@media (max-width: 379px) {
    body { padding: 10px 8px 24px; gap: 10px; }

    .app-logo { font-size: 2.6rem; }
    .header h1 { font-size: 1.9rem; letter-spacing: 0.18em; }
    .header .subtitle { font-size: 0.68rem; }

    .connect-btn { padding: 13px; font-size: 0.95rem; }
    .card { padding: 14px; }

    .control-pad { max-width: 270px; gap: 7px; }
    .ctrl-btn { font-size: 1.3rem; border-radius: 14px; }
    .ctrl-btn .btn-label { font-size: 0.52rem; }
    #btnStop { font-size: 0.75rem; }
}

/* md — large phones */
@media (min-width: 480px) and (max-width: 599px) {
    body { padding: 18px 16px 32px; gap: 14px; }
    .app-logo { font-size: 4rem; }
    .header h1 { font-size: clamp(2.4rem, 10vw, 3rem); }

    .control-pad { max-width: 360px; gap: 11px; }
    .ctrl-btn { font-size: 1.85rem; border-radius: 16px; }
    .ctrl-btn .btn-label { font-size: 0.65rem; }
    #btnStop { font-size: 1rem; }
}

/* lg — tablet portrait */
@media (min-width: 600px) and (max-width: 899px) {
    body { padding: 28px 24px 40px; gap: 20px; }

    .header, .connect-btn, .error-log,
    .card, .debug-section, .site-footer { max-width: 680px; }

    .app-logo { font-size: 5rem; }
    .header h1 { font-size: clamp(3rem, 8vw, 4rem); letter-spacing: 0.32em; }
    .header .subtitle { font-size: 0.88rem; }

    .connect-btn { padding: 20px; font-size: 1.15rem; border-radius: 20px; }
    .error-log { font-size: 0.85rem; }
    .card { padding: 28px; border-radius: 20px; }

    .control-pad { max-width: 420px; gap: 14px; }
    .ctrl-btn { font-size: 2.2rem; border-radius: 20px; border-width: 2px; }
    .ctrl-btn .btn-label { font-size: 0.7rem; }
    #btnStop { font-size: 1.1rem; }

    .key-hint kbd { font-size: 0.8rem; padding: 4px 12px; }
    .debug-table { font-size: 0.82rem; }
}

/* xl — tablet landscape / small desktop */
@media (min-width: 900px) {
    body { padding: 36px 32px 48px; gap: 24px; }

    .header, .connect-btn, .error-log,
    .card, .debug-section, .site-footer { max-width: 800px; }

    .app-logo { font-size: 5.5rem; }
    .header h1 { font-size: 4.2rem; letter-spacing: 0.36em; }
    .header .subtitle { font-size: 0.92rem; letter-spacing: 0.1em; }

    .connect-btn { padding: 22px; font-size: 1.2rem; border-radius: 22px; }
    .card { padding: 32px; border-radius: 22px; }

    .control-pad { max-width: 480px; gap: 16px; }
    .ctrl-btn { font-size: 2.6rem; border-radius: 22px; border-width: 2px; }
    .ctrl-btn .btn-label { font-size: 0.75rem; }
    #btnStop { font-size: 1.2rem; }

    .key-hint { margin-top: 20px; gap: 8px; }
    .key-hint kbd { font-size: 0.82rem; padding: 5px 14px; }

    .debug-table { font-size: 0.85rem; }
    .debug-table tr + tr td { padding-top: 8px; }

    .site-footer { padding-top: 32px; }
    .footer-name { font-size: 1rem; }
    .footer-tagline { font-size: 0.75rem; }
}

/* ---------- FOOTER ---------- */
.site-footer {
    width: 100%;
    max-width: 540px;
    text-align: center;
    padding: 24px 0 8px;
    margin-top: 8px;
}

.footer-divider {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 14px;
}

.footer-line {
    flex: 1;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--blue), transparent);
    opacity: 0.4;
    max-width: 120px;
}

.footer-dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--blue);
    box-shadow: 0 0 6px var(--blue-glow);
}

.footer-icon {
    font-size: 1.3rem;
    filter: drop-shadow(0 0 6px var(--blue-glow));
}

.footer-text {
    font-size: 0.82rem;
    margin-bottom: 4px;
    letter-spacing: 0.04em;
}

.footer-built {
    color: var(--text-dim);
    margin-right: 6px;
    text-transform: uppercase;
    font-size: 0.7rem;
    letter-spacing: 0.12em;
}

.footer-name {
    font-weight: 800;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    background: linear-gradient(90deg, var(--blue-light), #a78bfa, var(--blue-light));
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: name-shimmer 3s linear infinite;
}

@keyframes name-shimmer {
    0%   { background-position: 0%   center; }
    100% { background-position: 200% center; }
}

.footer-tagline {
    font-size: 0.68rem;
    color: var(--text-dim);
    letter-spacing: 0.08em;
    opacity: 0.6;
}