/* ===============================
   CALC — Professional UI
   Aesthetic: Dark Editorial / Mono
================================== */

@import url('https://fonts.googleapis.com/css2?family=DM+Mono:wght@300;400;500&family=Syne:wght@400;600;700;800&display=swap');

/* ---- Variables ---- */
:root {
    --bg: #0a0a0f;
    --surface: #111118;
    --surface2: #18181f;
    --border: rgba(255,255,255,0.07);
    --border-accent: rgba(99,202,183,0.3);
    --text: #e8e8f0;
    --text-muted: rgba(232,232,240,0.4);
    --text-dim: rgba(232,232,240,0.2);
    --accent: #63cab7;
    --accent2: #f0a05a;
    --danger: #e05c5c;
    --eq: #63cab7;
    --op: rgba(240,160,90,0.15);
    --op-text: #f0a05a;
    --num: rgba(255,255,255,0.04);
    --num-hover: rgba(255,255,255,0.08);
    --sci: rgba(99,202,183,0.07);
    --sci-hover: rgba(99,202,183,0.14);
    --shadow: 0 24px 60px rgba(0,0,0,0.6);
    --radius: 6px;
    --radius-lg: 14px;
    --mono: 'DM Mono', monospace;
    --display: 'Syne', sans-serif;
}

.light {
    --bg: #f4f3ef;
    --surface: #ffffff;
    --surface2: #f0efe9;
    --border: rgba(0,0,0,0.07);
    --border-accent: rgba(40,150,130,0.3);
    --text: #111118;
    --text-muted: rgba(17,17,24,0.45);
    --text-dim: rgba(17,17,24,0.2);
    --accent: #1a8a78;
    --accent2: #c47a2a;
    --danger: #c0392b;
    --eq: #1a8a78;
    --op: rgba(196,122,42,0.1);
    --op-text: #b06020;
    --num: rgba(0,0,0,0.03);
    --num-hover: rgba(0,0,0,0.07);
    --sci: rgba(26,138,120,0.06);
    --sci-hover: rgba(26,138,120,0.12);
    --shadow: 0 24px 60px rgba(0,0,0,0.1);
}

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

/* ---- Noise Overlay ---- */
.noise {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    opacity: 0.025;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    background-size: 200px;
}

body {
    font-family: var(--mono);
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 30px 20px 60px;
    transition: background 0.4s ease, color 0.4s ease;
    position: relative;
}

/* Subtle grid pattern */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
}

/* ---- Header ---- */
.app-header {
    position: relative;
    z-index: 2;
    text-align: center;
    margin-bottom: 36px;
}

.logo-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 18px;
}

.logo-mark {
    font-size: 28px;
    color: var(--accent);
    animation: spin 12s linear infinite;
    display: inline-block;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

h1 {
    font-family: var(--display);
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text);
}

.logo-dot { color: var(--accent); }

.version-tag {
    font-size: 10px;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-muted);
    border: 1px solid var(--border);
    padding: 3px 8px;
    border-radius: 20px;
    align-self: flex-end;
    margin-bottom: 4px;
}

.top-bar {
    display: flex;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.ctrl-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding: 8px 16px;
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 6px;
}

.ctrl-btn:hover {
    border-color: var(--border-accent);
    color: var(--accent);
    background: var(--surface2);
}

.btn-icon {
    font-size: 13px;
}

/* ---- Layout ---- */
.container {
    position: relative;
    z-index: 2;
    display: grid;
    grid-template-columns: 360px 240px;
    gap: 20px;
    justify-content: center;
    align-items: start;
    max-width: 640px;
    margin: auto;
}

/* ---- Calculator Card ---- */
.calculator {
    background: rgba(30, 41, 59, 0.7);
    backdrop-filter: blur(12px);
    padding: 25px;
    border-radius: 20px;
    box-shadow: 0 12px 35px rgba(0,0,0,0.4);
    width: 320px;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---- Section Label ---- */
.section-label {
    font-size: 9px;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-dim);
    margin-bottom: 10px;
    margin-top: 4px;
    padding-left: 2px;
}

/* ---- Display ---- */
.display-container {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 18px 12px;
    margin-bottom: 14px;
}

.display-label {
    font-size: 8px;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: var(--text-dim);
    margin-bottom: 8px;
}

.preview-line {
    font-size: 12px;
    color: var(--text-muted);
    text-align: right;
    min-height: 18px;
    font-family: var(--mono);
    letter-spacing: 0.05em;
}

#display {
    font-size: clamp(18px, 5vw, 28px);
    height: auto;
    min-height: 60px;
    width: 100%;
    background: transparent;
    border: none;
    outline: none;
    font-family: var(--display);
    font-weight: 700;
    color: var(--text);
    text-align: right;
    caret-color: var(--accent);
    padding: 6px 0;
    letter-spacing: -0.01em;
}

#display::placeholder { color: var(--text-dim); }

.display-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px solid var(--border);
}

#memIndicator {
    color: var(--accent2);
}

.hidden { visibility: hidden; }

/* ---- Memory Row ---- */
.memory-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
    margin-bottom: 14px;
}

.mem-btn {
    height: 34px;
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.05em;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.15s ease;
}

.mem-btn:hover {
    border-color: var(--border-accent);
    color: var(--accent);
    background: var(--sci);
}

.mem-btn.danger:hover {
    border-color: rgba(224,92,92,0.3);
    color: var(--danger);
    background: rgba(224,92,92,0.07);
}

/* ---- Scientific Buttons ---- */
.buttons.scientific {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
    margin-bottom: 14px;
}

.sci-btn {
    height: 40px;
    background: var(--sci);
    border: 1px solid var(--border);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 12px;
    letter-spacing: 0.02em;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.15s ease;
}

.sci-btn:hover {
    background: var(--sci-hover);
    border-color: var(--border-accent);
    transform: translateY(-1px);
}

.sci-btn:active { transform: scale(0.97); }

/* ---- Standard Buttons ---- */
.buttons.standard {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
    margin-bottom: 14px;
}

/* Base button style (reset) */
.num-btn, .op-btn, .action-btn, .eq-btn {
    height: 64px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-family: var(--display);
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
}

.num-btn {
    background: var(--num);
    color: var(--text);
}

.num-btn:hover {
    background: var(--num-hover);
    transform: translateY(-1px);
}

.num-btn:active { transform: scale(0.96); }

.op-btn {
    background: var(--op);
    color: var(--op-text);
    border-color: rgba(240,160,90,0.12);
    font-size: 20px;
}

.op-btn:hover {
    background: rgba(240,160,90,0.2);
    transform: translateY(-1px);
}

.action-btn {
    background: transparent;
    color: var(--text-muted);
    font-size: 14px;
    letter-spacing: 0.05em;
}

.action-btn:hover {
    color: var(--text);
    background: var(--num-hover);
}

.action-btn.danger { color: var(--danger); }
.action-btn.danger:hover { background: rgba(224,92,92,0.1); }

.eq-btn {
    background: var(--accent);
    color: #0a0a0f;
    border: none;
    font-size: 22px;
    box-shadow: 0 4px 20px rgba(99,202,183,0.25);
}

.eq-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(99,202,183,0.35);
}

.eq-btn:active { transform: scale(0.97); }

.zero { grid-column: span 2; }

/* ---- Tools ---- */
.tools {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    margin-top: 16px;
}

.tool-btn {
    background: var(--surface2);
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-family: var(--mono);
    font-size: 10px;
    letter-spacing: 0.05em;
    padding: 10px 6px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    text-transform: uppercase;
}

.tool-icon {
    font-size: 16px;
    color: var(--accent);
}

.tool-btn:hover {
    border-color: var(--border-accent);
    color: var(--text);
    background: var(--surface);
    transform: translateY(-2px);
}

/* ---- Graph ---- */
.graph-section {
    margin-top: 16px;
    background: var(--surface2);
    border: 1px solid var(--border);
    padding: 16px;
    border-radius: var(--radius);
    animation: slideUp 0.3s ease;
}

/* ---- History Panel ---- */
.history {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 20px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    animation: slideUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) 0.1s both;
    position: relative;
    overflow: hidden;
    background: rgba(30,41,59,0.7);
    backdrop-filter: blur(12px);
    border-radius: 20px;
    box-shadow: 0 10px 35px rgba(0,0,0,0.3);
    width: 100%;
    max-width: 380px;
    margin: auto;
}

.history::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
    opacity: 0.4;
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.clear-history {
    background: transparent;
    border: 1px solid rgba(224,92,92,0.25);
    color: var(--danger);
    font-family: var(--mono);
    font-size: 9px;
    letter-spacing: 0.15em;
    padding: 4px 10px;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.clear-history:hover {
    background: rgba(224,92,92,0.1);
}

#historyList {
    list-style: none;
    max-height: 340px;
    overflow-y: auto;
}

#historyList::-webkit-scrollbar { width: 3px; }
#historyList::-webkit-scrollbar-thumb {
    background: var(--border-accent);
    border-radius: 10px;
}

#historyList li {
    padding: 10px 8px;
    font-size: 12px;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    transition: all 0.15s ease;
    font-family: var(--mono);
    line-height: 1.5;
    border-radius: 4px;
}

#historyList li:hover {
    color: var(--text);
    background: var(--surface2);
    padding-left: 12px;
}

#historyList li .hi-result {
    color: var(--accent);
    font-weight: 500;
}

.history-empty {
    font-size: 11px;
    color: var(--text-dim);
    text-align: center;
    padding: 30px 0;
    letter-spacing: 0.1em;
}

/* ---- Toast ---- */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: var(--surface);
    border: 1px solid var(--border-accent);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 12px;
    letter-spacing: 0.1em;
    padding: 10px 24px;
    border-radius: 30px;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s ease;
    z-index: 100;
    white-space: nowrap;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ---- Mobile ---- */
@media (max-width: 680px) {
    body {
        padding: 15px;
    }
    header {
        margin-bottom: 20px;
    }
    .logo-row {
        flex-direction: column;
        gap: 8px;
    }
    .version-tag {
        align-self: center;
    }
    .container {
        display: flex;
        flex-direction: column;
        gap: 20px;
        max-width: 100%;
        margin: 0;
    }
    .calculator {
        width: 100%;
        max-width: none;
        padding: 20px;
    }
    .history {
        width: 100%;
        max-width: none;
    }
    .buttons {
        grid-template-columns: repeat(4, 1fr);
        gap: 10px;
    }
    .tools {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }
    .num-btn, .op-btn, .action-btn, .eq-btn, .sci-btn, .mem-btn {
        height: 60px;
        font-size: 17px;
    }
    h1 {
        font-size: 1.5rem;
    }
    .top-bar {
        gap: 6px;
    }
    .ctrl-btn {
        padding: 6px 12px;
        font-size: 10px;
    }
}