/* ============================================================
   app.css — Seminar Nasional PPs ULM 2026
   Premium, responsive stylesheet
   ============================================================ */

/* -- Reset & Base ------------------------------------------ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif; font-size: 1rem; line-height: 1.6; color: #1e293b; background: #f8fafc; }
img { max-width: 100%; height: auto; display: block; }
a { color: #2563eb; text-decoration: none; transition: color .2s; }
a:hover { color: #1e3a5f; }
ul, ol { list-style: none; }

/* -- Colors (CSS custom properties) ------------------------ */
:root {
    --primary: #1e3a5f;
    --accent: #2563eb;
    --success: #059669;
    --error: #dc2626;
    --warning: #d97706;
    --info: #2563eb;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,.1), 0 1px 2px rgba(0,0,0,.06);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,.1), 0 2px 4px -2px rgba(0,0,0,.1);
    --shadow-lg: 0 10px 25px -3px rgba(0,0,0,.1), 0 4px 6px -4px rgba(0,0,0,.1);
}

/* -- Container --------------------------------------------- */
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 1rem; }

/* -- Typography -------------------------------------------- */
h1, h2, h3, h4, h5, h6 { color: var(--primary); line-height: 1.3; font-weight: 700; }
h1 { font-size: 2.25rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.375rem; }
h4 { font-size: 1.125rem; }
p { margin-bottom: 1rem; }

/* -- Navbar ------------------------------------------------ */
.navbar { position: fixed; top: 0; left: 0; right: 0; z-index: 1000; background: rgba(255,255,255,.92); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid rgba(0,0,0,.06); transition: background .3s, box-shadow .3s; }
.navbar.scrolled { background: #fff; box-shadow: 0 1px 12px rgba(0,0,0,.08); }
.navbar-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.navbar-brand { display: flex; align-items: center; gap: .625rem; color: var(--primary); text-decoration: none; }
.brand-logo { display: flex; align-items: center; justify-content: center; width: 40px; height: 40px; background: linear-gradient(135deg, var(--primary), var(--accent)); border-radius: 10px; color: #fff; flex-shrink: 0; }
.brand-logo svg { stroke: #fff; width: 22px; height: 22px; }
.brand-logo-img { height: 40px; width: auto; border-radius: 6px; flex-shrink: 0; }
.brand-text-wrap { display: flex; flex-direction: column; line-height: 1.2; }
.brand-title { font-size: .875rem; font-weight: 800; letter-spacing: .04em; color: var(--primary); }
.brand-sub { font-size: .6875rem; font-weight: 500; color: var(--gray-500); }
.navbar-toggle { display: none; background: none; border: 1px solid var(--gray-200); cursor: pointer; padding: .5rem; border-radius: var(--radius); flex-direction: column; gap: 4px; }
.hamburger-line { display: block; width: 20px; height: 2px; background: var(--primary); border-radius: 2px; transition: transform .2s; }
.navbar-menu { display: flex; align-items: center; gap: .75rem; }
.nav-links { display: flex; gap: .125rem; align-items: center; }
.nav-link { padding: .5rem .75rem; font-size: .8125rem; font-weight: 500; color: var(--gray-600); border-radius: 6px; transition: color .2s, background .2s; white-space: nowrap; }
.nav-link:hover { color: var(--accent); background: rgba(37,99,235,.06); }
.nav-active { color: var(--accent); background: rgba(37,99,235,.08); font-weight: 600; }
.nav-caret { font-size: .625rem; margin-left: .125rem; opacity: .5; }
.nav-actions { display: flex; align-items: center; gap: .5rem; margin-left: .5rem; padding-left: .75rem; border-left: 1px solid var(--gray-200); }
.inline-form { display: inline; }

/* -- Navbar Dropdown --------------------------------------- */
.nav-dropdown { position: relative; }
.nav-dropdown-menu { display: none; position: absolute; top: 100%; left: 0; min-width: 200px; background: #fff; border: 1px solid var(--gray-200); border-radius: var(--radius); box-shadow: var(--shadow-lg); padding: .375rem 0; z-index: 1001; margin-top: .25rem; }
.nav-dropdown:hover .nav-dropdown-menu { display: block; }
.nav-dropdown-item { display: block; padding: .5rem 1rem; font-size: .8125rem; color: var(--gray-600); transition: all .15s; }
.nav-dropdown-item:hover { background: rgba(37,99,235,.08); color: var(--accent); }
.nav-dropdown-menu .nav-dropdown-item:hover { color: #2563eb; }

/* -- Buttons ----------------------------------------------- */
.btn { display: inline-flex; align-items: center; justify-content: center; padding: .5rem 1.125rem; font-size: .875rem; font-weight: 600; border-radius: var(--radius); border: 1px solid transparent; cursor: pointer; transition: all .2s; text-decoration: none; line-height: 1.4; }
.btn-sm { padding: .375rem .875rem; font-size: .8125rem; }
.btn-primary { background: linear-gradient(135deg, var(--primary), var(--accent)); color: #fff; border-color: var(--accent); }
.btn-primary:hover { opacity: .9; color: #fff; }
.btn-secondary { background: var(--gray-100); color: var(--gray-700); border-color: var(--gray-300); }
.btn-secondary:hover { background: var(--gray-200); }
.btn-outline { background: transparent; color: var(--primary); border-color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-danger { background: var(--error); color: #fff; border-color: var(--error); }
.btn-danger:hover { opacity: .9; color: #fff; }
.btn-warning { background: var(--warning); color: #fff; border-color: var(--warning); }
.btn-warning:hover { opacity: .9; color: #fff; }
.btn-success { background: var(--success); color: #fff; border-color: var(--success); }
.btn-success:hover { opacity: .9; color: #fff; }

/* -- Language Toggle --------------------------------------- */
.lang-toggle { display: flex; border: 1px solid var(--gray-300); border-radius: var(--radius); overflow: hidden; }
.lang-btn { padding: .25rem .625rem; font-size: .75rem; font-weight: 600; background: transparent; border: none; cursor: pointer; color: var(--gray-500); transition: all .2s; }
.lang-btn:first-child { border-right: 1px solid var(--gray-300); }
.lang-active { background: var(--primary); color: #fff; }

/* -- Flash Messages ---------------------------------------- */
.flash-message { display: flex; align-items: center; justify-content: space-between; padding: .75rem 1rem; margin: 1rem auto; max-width: 1200px; border-radius: var(--radius); font-size: .875rem; animation: flashIn .3s ease; }
.flash-success { background: #ecfdf5; color: #065f46; border: 1px solid #a7f3d0; }
.flash-error { background: #fef2f2; color: #991b1b; border: 1px solid #fecaca; }
.flash-warning { background: #fffbeb; color: #92400e; border: 1px solid #fde68a; }
.flash-info { background: #eff6ff; color: #1e40af; border: 1px solid #bfdbfe; }
.flash-close { background: none; border: none; font-size: 1.25rem; cursor: pointer; color: inherit; opacity: .6; padding: 0 .25rem; }
.flash-close:hover { opacity: 1; }
@keyframes flashIn { from { opacity: 0; transform: translateY(-8px); } to { opacity: 1; transform: translateY(0); } }

/* -- Main Content ------------------------------------------ */
.main-content { padding-top: 68px; min-height: calc(100vh - 68px); }

/* -- Cards ------------------------------------------------- */
.card { background: #fff; border-radius: var(--radius); box-shadow: var(--shadow); padding: 1.5rem; border: 1px solid var(--gray-200); }
.card-header { margin-bottom: 1rem; padding-bottom: .75rem; border-bottom: 1px solid var(--gray-200); }
.card-title { font-size: 1.125rem; font-weight: 700; color: var(--primary); }

/* -- Forms ------------------------------------------------- */
.form-group { margin-bottom: 1rem; }
.form-label { display: block; font-size: .8125rem; font-weight: 600; color: var(--gray-700); margin-bottom: .375rem; }
.form-input, .form-select, .form-textarea { width: 100%; padding: .625rem .75rem; border: 1px solid var(--gray-300); border-radius: var(--radius); font-size: .875rem; font-family: inherit; transition: border-color .2s, box-shadow .2s; background: #fff; }
.form-input:focus, .form-select:focus, .form-textarea:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px rgba(37,99,235,.1); }
.form-textarea { resize: vertical; min-height: 100px; }

/* -- Tables ------------------------------------------------ */
.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: .875rem; }
thead { background: var(--gray-50); }
th, td { padding: .75rem 1rem; text-align: left; border-bottom: 1px solid var(--gray-200); }
th { font-weight: 600; color: var(--gray-600); font-size: .8125rem; text-transform: uppercase; letter-spacing: .025em; }
tbody tr:hover { background: var(--gray-50); }

/* -- Banner Image (Full Width, Clear) ---------------------- */
.banner-section { width: 100%; overflow: hidden; background: #0a1628; }
.banner-img { width: 100%; height: auto; display: block; aspect-ratio: 1920 / 600; object-fit: cover; }

/* -- Hero Info Section ------------------------------------- */
.hero-info { background: linear-gradient(135deg, #0a1628 0%, var(--primary) 50%, #1a365d 100%); color: #fff; padding: 3.5rem 1rem 4rem; text-align: center; position: relative; overflow: hidden; }
.hero-info::before { content: ''; position: absolute; inset: 0; background: radial-gradient(ellipse at 30% 50%, rgba(37,99,235,.15) 0%, transparent 70%); }
.hero-info-inner { position: relative; z-index: 1; max-width: 800px; margin: 0 auto; }
.hero-badge { display: inline-block; padding: .375rem 1rem; background: rgba(255,255,255,.1); border: 1px solid rgba(255,255,255,.2); border-radius: 999px; font-size: .75rem; font-weight: 600; letter-spacing: .04em; text-transform: uppercase; margin-bottom: 1.25rem; backdrop-filter: blur(4px); }
.hero-info h1 { color: #fff; font-size: 2.25rem; margin-bottom: .75rem; font-weight: 800; letter-spacing: -.01em; line-height: 1.2; }
.hero-theme { font-size: 1rem; opacity: .85; max-width: 650px; margin: 0 auto 1.25rem; line-height: 1.7; }
.hero-meta { display: flex; align-items: center; justify-content: center; gap: 1.25rem; flex-wrap: wrap; font-size: .875rem; opacity: .8; margin-bottom: 1.75rem; }
.hero-meta-item { display: flex; align-items: center; gap: .375rem; }
.hero-actions { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; margin-top: .5rem; }
.btn-hero { padding: .75rem 2rem; font-size: .9375rem; border-radius: 10px; font-weight: 700; transition: all .2s; }
.btn-hero-primary { background: #fff; color: var(--primary); border: 2px solid #fff; }
a.btn-hero-primary:hover, .btn-hero-primary:hover { background: transparent; color: #fff; }
.btn-hero-ghost { background: transparent; color: #fff; border: 2px solid rgba(255,255,255,.4); }
a.btn-hero-ghost:hover, .btn-hero-ghost:hover { border-color: #fff; background: rgba(255,255,255,.1); color: #fff; }
.btn-hero-outline { background: transparent; color: #fff; border: 2px solid rgba(255,255,255,.4); }
a.btn-hero-outline:hover, .btn-hero-outline:hover { border-color: #fff; background: rgba(255,255,255,.15); color: #fff; }

/* -- Speaker Cards ----------------------------------------- */
.speaker-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 2rem; }
.speaker-card { text-align: center; padding: 2.5rem 1.5rem 2rem; border-radius: 12px; transition: transform .2s, box-shadow .2s; }
.speaker-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.speaker-photo { width: 130px; height: 130px; border-radius: 50%; object-fit: cover; margin: 0 auto 1.25rem; border: 4px solid #fff; box-shadow: 0 4px 20px rgba(37,99,235,.2); }
.speaker-name { font-size: 1.0625rem; font-weight: 700; color: var(--primary); margin-bottom: .25rem; }
.speaker-institution { font-size: .8125rem; color: var(--gray-500); margin-bottom: .5rem; }
.speaker-topic { font-size: .8125rem; color: var(--gray-600); line-height: 1.5; padding: .75rem; background: var(--gray-50); border-radius: 6px; margin-top: .75rem; }

/* -- Timeline ---------------------------------------------- */
.timeline { position: relative; padding-left: 2rem; }
.timeline::before { content: ''; position: absolute; left: .5rem; top: 0; bottom: 0; width: 2px; background: var(--gray-300); }
.timeline-item { position: relative; margin-bottom: 1.5rem; padding-left: 1.5rem; }
.timeline-item::before { content: ''; position: absolute; left: -1.625rem; top: .375rem; width: 12px; height: 12px; border-radius: 50%; background: var(--accent); border: 2px solid #fff; box-shadow: 0 0 0 2px var(--accent); }
.timeline-date { font-size: .8125rem; font-weight: 600; color: var(--accent); }
.timeline-title { font-size: 1rem; font-weight: 600; color: var(--primary); }
.timeline-desc { font-size: .875rem; color: var(--gray-500); }

/* -- FAQ Accordion ----------------------------------------- */
.faq-item { border: 1px solid var(--gray-200); border-radius: var(--radius); margin-bottom: .5rem; overflow: hidden; }
.faq-question { width: 100%; padding: 1rem 1.25rem; background: #fff; border: none; text-align: left; font-size: .9375rem; font-weight: 600; color: var(--primary); cursor: pointer; display: flex; justify-content: space-between; align-items: center; transition: background .2s; }
.faq-question:hover { background: var(--gray-50); }
.faq-question::after { content: '+'; font-size: 1.25rem; color: var(--gray-400); transition: transform .2s; }
.faq-item.open .faq-question::after { content: '−'; }
.faq-answer { padding: 0 1.25rem; max-height: 0; overflow: hidden; transition: max-height .3s ease, padding .3s ease; font-size: .875rem; color: var(--gray-600); }
.faq-item.open .faq-answer { max-height: 500px; padding: 0 1.25rem 1rem; }

/* -- Countdown --------------------------------------------- */
.countdown { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; min-height: 80px; align-items: center; }
.countdown-item { text-align: center; }
.countdown-value { font-size: 2.25rem; font-weight: 800; color: #fff; background: rgba(255,255,255,.12); backdrop-filter: blur(4px); border: 1px solid rgba(255,255,255,.15); border-radius: 12px; padding: .625rem 1.25rem; min-width: 72px; font-variant-numeric: tabular-nums; }
.countdown-label { font-size: .6875rem; text-transform: uppercase; letter-spacing: .08em; margin-top: .375rem; opacity: .7; font-weight: 500; }

/* -- Footer ------------------------------------------------ */
.site-footer { background: linear-gradient(180deg, #0a1628 0%, var(--primary) 100%); color: rgba(255,255,255,.8); padding: 3.5rem 0 1.5rem; margin-top: 0; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 2rem; margin-bottom: 2rem; }
.footer-brand { display: flex; align-items: center; gap: .625rem; color: #fff; font-weight: 700; font-size: 1rem; margin-bottom: .75rem; }
.footer-brand .brand-icon { color: #fff; }
.footer-theme { font-size: .8125rem; opacity: .6; line-height: 1.6; }
.footer-heading { font-size: .8125rem; font-weight: 700; color: #fff; margin-bottom: .75rem; text-transform: uppercase; letter-spacing: .05em; }
.footer-links li { margin-bottom: .5rem; }
.footer-links a { color: rgba(255,255,255,.6); font-size: .8125rem; transition: color .2s; }
.footer-links a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.1); padding-top: 1.25rem; text-align: center; font-size: .8125rem; opacity: .5; }

/* -- Utility Classes --------------------------------------- */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-muted { color: var(--gray-500); }
.text-success { color: var(--success); }
.text-error { color: var(--error); }
.text-warning { color: var(--warning); }
.mt-1 { margin-top: .5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: .5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.p-1 { padding: .5rem; }
.p-2 { padding: 1rem; }
.p-3 { padding: 1.5rem; }
.gap-1 { gap: .5rem; }
.gap-2 { gap: 1rem; }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }
.hidden { display: none; }
.section { padding: 4rem 0; }
.section-title { text-align: center; margin-bottom: 2.5rem; position: relative; }
.section-title::after { content: ''; display: block; width: 48px; height: 3px; background: linear-gradient(90deg, var(--accent), var(--primary)); margin: .75rem auto 0; border-radius: 2px; }
.section-subtitle { text-align: center; color: var(--gray-500); font-size: .9375rem; max-width: 600px; margin: -.75rem auto 2.5rem; }

/* -- Status Badges ----------------------------------------- */
.badge { display: inline-block; padding: .25rem .625rem; font-size: .75rem; font-weight: 600; border-radius: 999px; }
.badge-success { background: #ecfdf5; color: #065f46; }
.badge-error { background: #fef2f2; color: #991b1b; }
.badge-warning { background: #fffbeb; color: #92400e; }
.badge-info { background: #eff6ff; color: #1e40af; }
.badge-gray { background: var(--gray-100); color: var(--gray-600); }

/* -- Responsive: Tablet ------------------------------------ */
@media (max-width: 1023px) {
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    h1 { font-size: 1.875rem; }
    .hero h1 { font-size: 2rem; }
}

/* -- Responsive: Mobile ------------------------------------ */
@media (max-width: 767px) {
    .navbar-inner { height: 60px; }
    .navbar-toggle { display: flex; }
    .navbar-menu { display: none; position: absolute; top: 60px; left: 0; right: 0; background: #fff; flex-direction: column; padding: 1rem; border-bottom: 1px solid var(--gray-200); box-shadow: var(--shadow-lg); }
    .navbar-menu.open { display: flex; }
    .nav-links { flex-direction: column; width: 100%; }
    .nav-link { padding: .625rem .75rem; border-radius: 6px; }
    .nav-dropdown-menu { position: static; box-shadow: none; border: none; padding-left: 1rem; margin-top: 0; }
    .nav-dropdown:hover .nav-dropdown-menu { display: block; }
    .nav-actions { flex-direction: column; width: 100%; gap: .5rem; margin: .75rem 0 0; padding: .75rem 0 0; border-left: none; border-top: 1px solid var(--gray-200); margin-left: 0; }
    .nav-actions .btn { width: 100%; text-align: center; }
    .nav-actions .lang-toggle { align-self: center; }
    .footer-grid { grid-template-columns: 1fr; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    h1 { font-size: 1.5rem; }
    .hero-info { padding: 2.5rem 1rem 3rem; }
    .hero-info h1 { font-size: 1.5rem; }
    .hero-meta { flex-direction: column; gap: .5rem; }
    .countdown-value { font-size: 1.5rem; padding: .5rem .875rem; min-width: 56px; }
    .section { padding: 2.5rem 0; }
    .main-content { padding-top: 60px; }
}