/* =====================================================================
   style.css
   ---------
   Sistem desain kustom untuk aplikasi PDA HTML Validator.

   TOKEN WARNA
   - --ink     : latar gelap (hero, footer, panel state)
   - --paper   : latar terang utama, abu-hangat (bukan putih polos)
   - --text    : warna teks utama
   - --slate   : warna teks sekunder / meta
   - --line    : warna garis pembatas tipis
   - --teal    : aksen utama (aksi PUSH, tautan, tombol primer)
   - --amber   : aksen kedua (aksi POP, peringatan halus)
   - --danger  : status gagal / tidak valid
   - --success : status berhasil / valid

   TIPOGRAFI
   - --font-mono : IBM Plex Mono -> dipakai untuk kode, nama tag, dan
                   elemen yang merepresentasikan "mesin" (state, stack)
   - --font-sans : IBM Plex Sans -> teks naratif / body copy
   ===================================================================== */

:root {
    --ink: #12172B;
    --ink-soft: #1B2140;
    --paper: #F7F7F4;
    --surface: #FFFFFF;
    --text: #1B2130;
    --slate: #5B6478;
    --line: #E3E5E4;

    --teal: #0E7C7B;
    --teal-dark: #0A5F5E;
    --amber: #E29A3C;
    --danger: #C6432E;
    --success: #1E7D5C;

    --font-mono: 'IBM Plex Mono', 'SFMono-Regular', Consolas, monospace;
    --font-sans: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 18px;
    --shadow-soft: 0 8px 24px rgba(18, 23, 43, 0.06);
    --shadow-lift: 0 16px 40px rgba(18, 23, 43, 0.12);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-sans);
    color: var(--text);
    background-color: var(--paper);
    line-height: 1.65;
}

/* Menghormati preferensi pengguna yang mengurangi animasi */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}

h1, h2, h3, h4, h5, .display-font {
    font-family: var(--font-sans);
    font-weight: 700;
    letter-spacing: -0.01em;
    color: var(--ink);
}

code, .mono, .font-mono { font-family: var(--font-mono); }

a { color: var(--teal); text-decoration: none; }
a:hover { color: var(--teal-dark); }

::selection { background: var(--teal); color: white; }

/* Fokus keyboard yang jelas & konsisten (aksesibilitas) */
a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible, select:focus-visible {
    outline: 2px solid var(--teal);
    outline-offset: 2px;
}

/* =====================================================================
   NAVBAR
   ===================================================================== */
.app-navbar {
    background: rgba(247, 247, 244, 0.92);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--line);
    padding-top: 0.85rem;
    padding-bottom: 0.85rem;
}

.brand-mark {
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--ink);
    letter-spacing: -0.02em;
}

.brand-sub {
    font-family: var(--font-mono);
    color: var(--teal);
    font-weight: 500;
    font-size: 1.05rem;
}

.app-navbar .nav-link {
    font-weight: 500;
    color: var(--slate);
    padding: 0.5rem 0.9rem;
    position: relative;
}

.app-navbar .nav-link.active,
.app-navbar .nav-link:hover {
    color: var(--ink);
}

.app-navbar .nav-link.active::after {
    content: "";
    position: absolute;
    left: 0.9rem;
    right: 0.9rem;
    bottom: 0.1rem;
    height: 2px;
    background: var(--teal);
    border-radius: 2px;
}

.btn-brand-primary {
    background: var(--ink);
    color: #fff;
    border: 1px solid var(--ink);
    font-weight: 600;
    border-radius: var(--radius-sm);
    transition: transform 0.15s ease, background 0.15s ease;
}

.btn-brand-primary:hover {
    background: var(--teal-dark);
    border-color: var(--teal-dark);
    color: #fff;
    transform: translateY(-1px);
}

.btn-brand-outline {
    border: 1.5px solid var(--ink);
    color: var(--ink);
    font-weight: 600;
    border-radius: var(--radius-sm);
    background: transparent;
}

.btn-brand-outline:hover {
    background: var(--ink);
    color: #fff;
}

/* =====================================================================
   HERO (Home)
   ===================================================================== */
.hero {
    background: var(--ink);
    color: #EDEEF4;
    position: relative;
    overflow: hidden;
    padding: 5.5rem 0 6rem;
}

.hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
    background-size: 42px 42px;
    pointer-events: none;
}

.hero .eyebrow {
    font-family: var(--font-mono);
    color: var(--amber);
    font-size: 0.8rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-weight: 600;
}

.hero h1 {
    color: #fff;
    font-size: clamp(2.1rem, 4.2vw, 3.4rem);
    line-height: 1.1;
    max-width: 16ch;
}

.hero p.lead {
    color: #B9BECF;
    max-width: 46ch;
    font-size: 1.1rem;
}

.hero-panel {
    background: rgba(255,255,255,0.03);
    border: 1px solid rgba(255,255,255,0.09);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    backdrop-filter: blur(6px);
}

/* --- Signature element: simulasi stack PDA yang berjalan otomatis --- */
.stack-demo {
    font-family: var(--font-mono);
    font-size: 0.85rem;
}

.stack-demo-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #8A93AC;
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin-bottom: 0.75rem;
}

.stack-demo-body {
    display: flex;
    flex-direction: column-reverse;
    gap: 0.4rem;
    min-height: 190px;
    justify-content: flex-start;
    padding: 0.6rem;
    border: 1px dashed rgba(255,255,255,0.14);
    border-radius: var(--radius-md);
}

.stack-chip {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(14, 124, 123, 0.16);
    border: 1px solid rgba(14, 124, 123, 0.45);
    color: #CFEDEA;
    border-radius: var(--radius-sm);
    padding: 0.4rem 0.7rem;
    animation: chipIn 0.35s ease;
}

.stack-chip.base {
    background: rgba(255,255,255,0.06);
    border-color: rgba(255,255,255,0.16);
    color: #9AA1B5;
}

@keyframes chipIn {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}

.stack-log {
    margin-top: 0.9rem;
    color: #9AA1B5;
    font-size: 0.78rem;
    min-height: 1.4em;
}

.stack-log .tag-push { color: var(--teal); }
.stack-log .tag-pop { color: var(--amber); }

/* =====================================================================
   SECTIONS UMUM
   ===================================================================== */
.section { padding: 5rem 0; }
.section-tight { padding: 3.5rem 0; }

.section-eyebrow {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--teal-dark);
    font-weight: 600;
}

.section-title { font-size: clamp(1.6rem, 3vw, 2.2rem); }

.section-lead { color: var(--slate); max-width: 60ch; }

.card-feature {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius-md);
    padding: 1.75rem;
    height: 100%;
    transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}

.card-feature:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-soft);
    border-color: rgba(14, 124, 123, 0.35);
}

.feature-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-sm);
    background: rgba(14, 124, 123, 0.1);
    color: var(--teal-dark);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    margin-bottom: 1rem;
}

.step-item {
    display: flex;
    gap: 1rem;
    padding: 1.1rem 0;
    border-bottom: 1px solid var(--line);
}

.step-item:last-child { border-bottom: none; }

.step-index {
    font-family: var(--font-mono);
    color: var(--teal-dark);
    font-weight: 700;
    min-width: 2.4rem;
}

/* =====================================================================
   VALIDATOR PAGE
   ===================================================================== */
.validator-shell {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-soft);
    overflow: hidden;
}

.validator-toolbar {
    background: var(--ink);
    color: #fff;
    padding: 0.85rem 1.25rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.validator-toolbar .dot-group span {
    display: inline-block;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    margin-right: 6px;
}

textarea#htmlInput {
    font-family: var(--font-mono);
    font-size: 0.92rem;
    background: #FBFBF9;
    border: none;
    border-right: 1px solid var(--line);
    resize: vertical;
    min-height: 360px;
    padding: 1.25rem;
    width: 100%;
    color: var(--text);
}

textarea#htmlInput:focus { outline: none; background: #fff; }

.result-panel {
    padding: 1.25rem;
    min-height: 360px;
}

.status-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.9rem;
    border-radius: 999px;
    font-weight: 600;
    font-size: 0.9rem;
}

.status-badge.valid { background: rgba(30, 125, 92, 0.12); color: var(--success); }
.status-badge.invalid { background: rgba(198, 67, 46, 0.12); color: var(--danger); }
.status-badge.idle { background: rgba(91, 100, 120, 0.12); color: var(--slate); }

.trace-table {
    font-family: var(--font-mono);
    font-size: 0.82rem;
}

.trace-table th {
    font-family: var(--font-sans);
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--slate);
    border-bottom: 2px solid var(--line);
}

.trace-table td { vertical-align: top; border-bottom: 1px solid var(--line); }

.action-pill {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.15rem 0.5rem;
    border-radius: 5px;
    letter-spacing: 0.03em;
}

.action-pill.PUSH { background: rgba(14,124,123,0.14); color: var(--teal-dark); }
.action-pill.POP { background: rgba(226,154,60,0.16); color: #8A5A16; }
.action-pill.SKIP { background: rgba(91,100,120,0.12); color: var(--slate); }
.action-pill.REJECT { background: rgba(198,67,46,0.16); color: var(--danger); }
.action-pill.ACCEPT { background: rgba(30,125,92,0.16); color: var(--success); }

.stack-visual {
    display: flex;
    flex-direction: column-reverse;
    gap: 0.3rem;
    font-family: var(--font-mono);
    font-size: 0.72rem;
}

.stack-visual span {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 4px;
    padding: 0.1rem 0.4rem;
    display: inline-block;
    width: fit-content;
}

.example-chip {
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    padding: 0.85rem 1rem;
    cursor: pointer;
    transition: border-color 0.15s ease, background 0.15s ease;
    background: var(--surface);
}

.example-chip:hover { border-color: var(--teal); background: rgba(14,124,123,0.04); }

.example-chip .tag-valid { color: var(--success); }
.example-chip .tag-invalid { color: var(--danger); }

/* =====================================================================
   FOOTER
   ===================================================================== */
.app-footer {
    background: var(--ink);
    color: #B9BECF;
    margin-top: 4rem;
}

.app-footer a { color: #D7DAE6; }
.app-footer a:hover { color: #fff; }

.footer-heading {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: #7C84A0;
    margin-bottom: 0.8rem;
}

.footer-links li { margin-bottom: 0.5rem; }
.footer-text { color: #9AA1B5; font-size: 0.92rem; }
.footer-divider { border-color: rgba(255,255,255,0.1); margin: 2rem 0 1.25rem; }
.footer-copy { color: #767E99; font-family: var(--font-mono); font-size: 0.78rem; }

/* =====================================================================
   RESPONSIVE
   ===================================================================== */
@media (max-width: 991.98px) {
    textarea#htmlInput { border-right: none; border-bottom: 1px solid var(--line); min-height: 260px; }
    .hero { padding: 3.5rem 0 4rem; text-align: left; }
}