/* ================================================================
   AFFAS – app.css  |  Design System & Formulas Page
   ================================================================ */

/* ── Design Tokens ──────────────────────────────────────────────── */
:root {
    --cyan:          #00d4ff;
    --cyan-dim:      rgba(0, 212, 255, 0.12);
    --cyan-border:   rgba(0, 212, 255, 0.25);
    --green:         #00ffa3;
    --green-dim:     rgba(0, 255, 163, 0.10);
    --purple:        #7c3aed;
    --purple-dim:    rgba(124, 58, 237, 0.12);
    --danger:        #f43f5e;

    --bg:            #050814;
    --bg2:           #0b1023;
    --surface:       rgba(255, 255, 255, 0.04);
    --surface2:      rgba(255, 255, 255, 0.07);
    --border:        rgba(255, 255, 255, 0.08);
    --border-hover:  rgba(255, 255, 255, 0.18);

    --text:          #e2e8f0;
    --text-muted:    #64748b;
    --text-dim:      #94a3b8;

    --radius-sm:     10px;
    --radius-md:     16px;
    --radius-lg:     22px;
    --radius-xl:     30px;

    --font-main:     'Space Grotesk', sans-serif;
    --font-mono:     'JetBrains Mono', monospace;

    --shadow:        0 8px 32px rgba(0,0,0,0.4);
    --shadow-lg:     0 24px 60px rgba(0,0,0,0.5);
}

/* Light Theme */
body.light-theme {
    --bg:        #f0f4ff;
    --bg2:       #e8edf8;
    --surface:   rgba(255,255,255,0.8);
    --surface2:  rgba(255,255,255,0.95);
    --border:    rgba(0,0,0,0.08);
    --border-hover: rgba(0,0,0,0.18);
    --text:      #1e293b;
    --text-muted:#64748b;
    --text-dim:  #475569;
    --cyan:      #0284c7;
    --cyan-dim:  rgba(2,132,199,0.08);
    --cyan-border: rgba(2,132,199,0.25);
}

/* ── Reset ──────────────────────────────────────────────────────── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: var(--font-main);
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    overflow-x: hidden;
    transition: background 0.4s, color 0.4s;
}

/* ── Shared Background Effects ──────────────────────────────────── */
#stars { position: fixed; inset: 0; z-index: 0; pointer-events: none; }
.star {
    position: absolute;
    background: white;
    border-radius: 50%;
    animation: twinkle var(--dur, 3s) ease-in-out infinite;
}
@keyframes twinkle {
    0%,100% { opacity: 0.1; transform: scale(1); }
    50%      { opacity: 0.85; transform: scale(1.4); }
}

body.light-theme .star { background: #94a3b8; opacity: 0.15 !important; animation: none; }

.mesh-bg {
    position: fixed; inset: 0;
    z-index: 0; pointer-events: none; overflow: hidden;
}
.mesh-bg::before {
    content: '';
    position: absolute;
    width: 800px; height: 800px; border-radius: 50%;
    background: radial-gradient(circle, rgba(0,212,255,0.10) 0%, transparent 70%);
    top: -200px; left: -200px;
    animation: driftA 22s ease-in-out infinite alternate;
}
.mesh-bg::after {
    content: '';
    position: absolute;
    width: 700px; height: 700px; border-radius: 50%;
    background: radial-gradient(circle, rgba(124,58,237,0.08) 0%, transparent 70%);
    bottom: -150px; right: -150px;
    animation: driftB 18s ease-in-out infinite alternate;
}
.mesh-green {
    position: fixed;
    width: 500px; height: 500px; border-radius: 50%;
    background: radial-gradient(circle, rgba(0,255,163,0.07) 0%, transparent 70%);
    bottom: 20%; left: 30%;
    pointer-events: none; z-index: 0;
    animation: driftC 28s ease-in-out infinite alternate;
}
.grid-canvas {
    position: fixed; inset: 0; z-index: 0; pointer-events: none;
    background-image:
        linear-gradient(rgba(0,212,255,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,212,255,0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    -webkit-mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.35) 0%, transparent 75%);
    mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.35) 0%, transparent 75%);
}
@keyframes driftA { from { transform: translate(0,0) scale(1); } to { transform: translate(100px,70px) scale(1.2); } }
@keyframes driftB { from { transform: translate(0,0) scale(1); } to { transform: translate(-70px,-50px) scale(1.15); } }
@keyframes driftC { from { transform: translate(0,0); } to { transform: translate(50px,-30px); } }

body.light-theme .mesh-bg::before { background: radial-gradient(circle, rgba(2,132,199,0.06) 0%, transparent 70%); }
body.light-theme .mesh-bg::after  { background: radial-gradient(circle, rgba(124,58,237,0.04) 0%, transparent 70%); }
body.light-theme .mesh-green { opacity: 0.3; }
body.light-theme .grid-canvas { opacity: 0.5; }

/* ── App Layout ─────────────────────────────────────────────────── */
.app-layout {
    position: relative; z-index: 1;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ── App Header ─────────────────────────────────────────────────── */
.app-header {
    position: sticky; top: 0; z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 32px;
    height: 64px;
    background: rgba(5,8,20,0.75);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: background 0.4s, border-color 0.4s;
}

body.light-theme .app-header {
    background: rgba(240,244,255,0.85);
    border-color: var(--border);
}

.app-logo {
    font-family: var(--font-mono);
    font-size: 1.3rem;
    font-weight: 600;
    background: linear-gradient(135deg, var(--cyan), var(--green));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-decoration: none;
    letter-spacing: -0.5px;
    flex-shrink: 0;
}

.app-nav {
    display: flex;
    align-items: center;
    gap: 4px;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.86rem;
    font-weight: 500;
    color: var(--text-muted);
    text-decoration: none;
    transition: all 0.2s;
    border: 1px solid transparent;
    white-space: nowrap;
}

.nav-link:hover {
    color: var(--cyan);
    background: var(--cyan-dim);
    border-color: var(--cyan-border);
}

.nav-link.active {
    color: var(--cyan);
    background: var(--cyan-dim);
    border-color: var(--cyan-border);
}

.nav-link.icon-btn {
    padding: 7px 10px;
    font-size: 0.95rem;
}

/* ── App Main ────────────────────────────────────────────────────── */
.app-main {
    flex: 1;
    padding: 36px 32px 80px;
    max-width: 1280px;
    margin: 0 auto;
    width: 100%;
}

/* ── Page Header ─────────────────────────────────────────────────── */
.page-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    margin-bottom: 28px;
    gap: 16px;
    flex-wrap: wrap;
}

.page-header-text h1 {
    font-size: clamp(1.6rem, 3vw, 2.2rem);
    font-weight: 700;
    letter-spacing: -0.5px;
    background: linear-gradient(135deg, #fff, var(--text-dim));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

body.light-theme .page-header-text h1 {
    background: linear-gradient(135deg, #1e293b, #475569);
    -webkit-background-clip: text;
    background-clip: text;
}

.page-header-text p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 4px;
}

.pill-btn {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 9px 18px;
    border-radius: 50px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-dim);
    font-size: 0.84rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.25s;
    font-family: var(--font-main);
}

.pill-btn:hover {
    border-color: #f59e0b;
    color: #f59e0b;
    background: rgba(245,158,11,0.08);
}

.pill-btn i { font-size: 0.8rem; }

/* ── Search ──────────────────────────────────────────────────────── */
.search-area { margin-bottom: 32px; }

.search-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    max-width: 600px;
}

.search-wrapper > i {
    position: absolute;
    left: 18px;
    color: var(--text-muted);
    font-size: 0.95rem;
    pointer-events: none;
}

#search-input {
    flex: 1;
    padding: 14px 18px 14px 46px;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-md) 0 0 var(--radius-md);
    background: var(--surface);
    color: var(--text);
    font-family: var(--font-main);
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.25s, box-shadow 0.25s, background 0.4s;
    backdrop-filter: blur(10px);
}

#search-input::placeholder { color: var(--text-muted); }

#search-input:focus {
    border-color: var(--cyan-border);
    box-shadow: 0 0 0 3px rgba(0,212,255,0.08);
    background: var(--surface2);
}

.search-btn {
    padding: 14px 24px;
    background: linear-gradient(135deg, var(--cyan), var(--green));
    color: #050814;
    font-family: var(--font-main);
    font-size: 0.92rem;
    font-weight: 700;
    border: none;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.2s;
    white-space: nowrap;
}

.search-btn:hover { opacity: 0.88; }
.search-btn:active { transform: scale(0.97); }

/* ── Formulas Grid ───────────────────────────────────────────────── */
.formulas-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 18px;
    animation: fadeInGrid 0.5s ease-out;
}

@keyframes fadeInGrid {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ── Formula Card ────────────────────────────────────────────────── */
.formula-card {
    position: relative;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
}

/* Top accent line */
.formula-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--cyan), var(--green));
    opacity: 0;
    transition: opacity 0.3s;
}

.formula-card:hover {
    border-color: var(--cyan-border);
    background: var(--surface2);
    transform: translateY(-4px);
    box-shadow: 0 16px 40px rgba(0,0,0,0.3), 0 0 0 1px var(--cyan-border);
}

.formula-card:hover::before { opacity: 1; }

/* Favorite icon */
.favorite-icon {
    position: absolute;
    top: 14px; right: 16px;
    font-size: 1rem;
    color: var(--border-hover);
    cursor: pointer;
    transition: all 0.25s;
    z-index: 2;
    padding: 4px;
    border-radius: 6px;
}

.favorite-icon:hover { color: #f59e0b; transform: scale(1.2); }
.favorite-icon.active { color: #f59e0b; text-shadow: 0 0 12px rgba(245,158,11,0.5); }

/* Formula symbol */
.formula-symbol {
    font-family: var(--font-mono);
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--cyan);
    padding: 12px 16px;
    background: var(--cyan-dim);
    border-radius: var(--radius-sm);
    border: 1px solid var(--cyan-border);
    text-align: center;
    letter-spacing: 0.5px;
    transition: background 0.3s;
}

.formula-card:hover .formula-symbol {
    background: rgba(0,212,255,0.18);
}

.formula-name {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin: 0;
    line-height: 1.3;
}

.formula-description {
    font-size: 0.84rem;
    color: var(--text-muted);
    line-height: 1.6;
    flex: 1;
}

.calculate-button {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 7px;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--cyan-border);
    background: var(--cyan-dim);
    color: var(--cyan);
    font-family: var(--font-main);
    font-size: 0.84rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.25s;
    margin-top: auto;
}

.calculate-button:hover {
    background: rgba(0,212,255,0.22);
    transform: none;
}

.calculate-button::before { content: '⚡'; font-size: 0.8rem; }

/* ── No Results ──────────────────────────────────────────────────── */
.no-results {
    text-align: center;
    grid-column: 1/-1;
    padding: 80px 20px;
    color: var(--text-muted);
}
.no-results .no-icon { font-size: 3rem; margin-bottom: 16px; }
.no-results p { font-size: 1rem; }

/* ── Modal ───────────────────────────────────────────────────────── */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    z-index: 1000;
    background: rgba(5,8,20,0.85);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    align-items: center;
    justify-content: center;
    padding: 24px;
    overflow-y: auto;
}

.modal-overlay.open {
    display: flex;
    animation: modalIn 0.3s ease-out;
}

@keyframes modalIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

.modal-box {
    position: relative;
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: 40px;
    width: 100%;
    max-width: 580px;
    box-shadow: var(--shadow-lg), 0 0 0 1px rgba(0,212,255,0.1);
    animation: boxIn 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes boxIn {
    from { opacity: 0; transform: scale(0.92) translateY(20px); }
    to   { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-close {
    position: absolute;
    top: 18px; right: 20px;
    width: 36px; height: 36px;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-muted);
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.modal-close:hover { background: var(--surface2); color: var(--danger); border-color: var(--danger); }

/* Modal body content */
.formula-detail-symbol {
    font-family: var(--font-mono);
    font-size: 2.2rem;
    font-weight: 600;
    color: var(--cyan);
    text-align: center;
    background: var(--cyan-dim);
    border: 1px solid var(--cyan-border);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-bottom: 20px;
    letter-spacing: 1px;
    box-shadow: 0 0 40px rgba(0,212,255,0.1);
}

.formula-detail-name {
    font-size: 1.6rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 8px;
    color: var(--text);
}

.formula-detail-description {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 28px;
    line-height: 1.65;
}

.formula-usage {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 18px;
    margin-bottom: 24px;
}

.formula-usage h3 {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--cyan);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 10px;
}

.formula-usage p { font-size: 0.9rem; color: var(--text-dim); line-height: 1.6; }

.calculation-area h3 {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--cyan);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 16px;
    text-align: center;
}

.variables-input {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-bottom: 18px;
}

.variable-input { flex: 1; min-width: 200px; }

.variable-input label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 6px;
    font-weight: 500;
}

.variable-input input {
    width: 100%;
    padding: 11px 14px;
    border-radius: var(--radius-sm);
    border: 1.5px solid var(--border);
    background: var(--surface);
    color: var(--text);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.variable-input input:focus {
    border-color: var(--cyan-border);
    box-shadow: 0 0 0 3px rgba(0,212,255,0.08);
}

.calculate-result-button {
    width: 100%;
    padding: 14px;
    border-radius: var(--radius-md);
    border: none;
    background: linear-gradient(135deg, var(--cyan), var(--green));
    color: #050814;
    font-family: var(--font-main);
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.2s;
    letter-spacing: 0.2px;
}

.calculate-result-button:hover { opacity: 0.88; }
.calculate-result-button:active { transform: scale(0.98); }

#result-area {
    margin-top: 18px;
    padding: 20px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    display: none;
    border-left: 3px solid var(--green);
}

#result-area h3 {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--green);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 10px;
}

.result-value {
    font-family: var(--font-mono);
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    word-break: break-all;
    line-height: 1.6;
}

/* ── Responsive ──────────────────────────────────────────────────── */
@media (max-width: 768px) {
    .app-header { padding: 0 16px; }
    .nav-link span { display: none; }
    .nav-link { padding: 7px 10px; gap: 0; }
    .app-main { padding: 24px 16px 60px; }
    .page-header { flex-direction: column; align-items: flex-start; }
    .search-wrapper { max-width: 100%; }
    .formulas-container { grid-template-columns: 1fr; }
    .modal-box { padding: 28px 20px 24px; border-radius: var(--radius-lg); }
    .formula-detail-symbol { font-size: 1.6rem; }
    .formula-detail-name { font-size: 1.3rem; }
    .variable-input { min-width: 100%; }
}

@media (max-width: 480px) {
    .search-wrapper { flex-direction: column; align-items: stretch; }
    #search-input { border-radius: var(--radius-md); margin-bottom: 8px; }
    .search-btn { border-radius: var(--radius-md); }
    .formula-detail-symbol { font-size: 1.3rem; }
}