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


*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
#theme-toggle img {
    width: 20px;
    height: 20px;
}

[data-theme="dark"] #theme-toggle img {
    filter: brightness(0) invert(1);
}
nav {
    position: fixed;
    top: 16px;
    right: 16px;
    z-index: 1000;
    
}
:root {
    --bg: #F5F7FC;
    --surface: #FFFFFF;
    --surface2: #EEF2F8;
    --border: #D9DFEB;

    --accent: #8EA2FF;       /* slightly stronger pastel */
    --accent-soft: #C7D2FE;
    --accent-dim: #6F84F5;

    --text: #2B2F3A;
    --muted: #8A90A3;
    --danger: #F28B82;

    --back: #E9EDFF;
    --backHover: #DCE3FF;

    --danger-bg: #FFE4E4;
    --danger-border: #F5B5B5;

    --mono: 'JetBrains Mono', monospace;
    --sans: 'Syne', sans-serif;
}

[data-theme="dark"] {
    --bg: #0B0C10;
    --surface: #111318;
    --surface2: #181B22;
    --border: #262A33;

    --accent: #4F8CFF;
    --accent-soft: #1f0962;
    --accent-dim: #3A6FD9;

    --text: #E8ECF1;
    --muted: #8B93A7;
    --danger: #FF5C5C;

    /* fix utility colors */
    --back: #1A2230;
    --backHover: #222B3A;

    --danger-bg: #2A1414;
    --danger-border: #3A1C1C;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--mono);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 1rem;
}

.container {
    width: 100%;
    max-width: 380px;
}

h1 {
    font-family: var(--sans);
    font-size: 13px;
    font-weight: 400;
    color: var(--muted);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin-bottom: 1.25rem;
}

/* Display */
.display {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px 20px;
    margin-bottom: 14px;
    min-height: 110px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    text-align: right;
}

#expression {
    font-family: var(--mono);
    font-size: 14px;
    color: var(--muted);
    min-height: 20px;
    word-break: break-all;
    letter-spacing: 0.03em;
    text-align: left; 
    width: 100%;
}

.result-row {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    margin-top: 8px;
    text-align: right; 
}

#res {
    font-size: 28px;
    font-weight: 600;
    color: var(--accent);
    letter-spacing: -0.02em;
    min-height: 36px;
    transition: color 0.2s;
    text-align: right;
    margin-top: auto;
}

#status {
    font-size: 11px;
    color: var(--danger);
    padding-bottom: 4px;
}

/* Buttons */
.btn-grid {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 7px;
    margin-bottom: 7px;
}

.btn-grid button {
    grid-column: span 2;
}

.btn-row {
    display: grid;    grid-template-columns: repeat(8, 1fr); 
    gap: 7px;
    margin-bottom: 7px;
}

.btn-row button {
    grid-column: span 4; 
    width: 100%;
}

.btn-grid .btn-par {
    grid-column: span 1;
    width: 100%; 
}


.exp-row {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 7px;
    margin-bottom: 14px;
}

button {
    padding: 14px 8px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--surface);
    color: var(--text);
    font-size: 16px;
    font-family: var(--mono);
    cursor: pointer;
    transition: background 0.1s, transform 0.08s, border-color 0.1s;
    line-height: 1;
    height: 48px;
}

button:hover { background: var(--surface2); border-color: var(--accent-dim); }
button:active { transform: scale(0.95); }

.btn-op {
    color: var(--accent);
    font-size: 25px;
    
}

.btn-fn {
    font-size: 13px;
    color: var(--text);
    background: var(--accent-soft);
    border-color: var(--border);
}
.btn-fn:hover { 
    background: var(--accent);
    color: white 
}


.btn-clear {
    background: var(--danger-bg);
    color: var(--danger);
    border-color: var(--danger-border);
}
.btn-clear:hover,
.btn-back:hover{ background: var(--backHover); }

.btn-back {
    font-size: 24px;
    padding-top: 10px;    
    padding-bottom: 10px; 
    color: var(--text);
    background: var(--back);
    border-color: var(--border);
}


.btn-eq {
    background: var(--accent);
    color: #ffffff;
    font-weight: 600;
    border-color: var(--accent-dim);
    font-size: 14px;
    letter-spacing: 0.05em;
    
}
.btn-eq:hover { 
    background: var(--accent-dim);
    
}

.btn-delete-log {
    background: none;
    border: none;
    color: var(--danger);
    font-size: 16px;
    font-weight: bolder;
    cursor: pointer;
    padding: 0 4px;
    height: auto;
    line-height: 1;
    opacity: 0.5;
    transition: opacity 0.15s, color 0.15s;
}
.btn-delete-log:hover {
    color: var(--danger);
    opacity: 1;
    background: none;
    transform: none;
}

.log-right {
    display: flex;
    align-items: end;
    gap: 6px;
    flex-shrink: 0;
}

#res.error-text {
    color: #ff4d4d !important;   
    font-size: 14px !important;  
    font-weight: 700;
    text-align: right;
}

/* Exponent n row */
.exp-n-wrapper {
    display: grid;
    grid-template-columns: 1fr 120px 1fr;
    gap: 7px;
    margin-bottom: 14px;
    align-items: stretch;
}

#exp-n-input {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    font-family: var(--mono);
    font-size: 14px;
    padding: 0 10px;
    text-align: center;
    outline: none;
    transition: border-color 0.15s;
    width: 100%;
}
#exp-n-input:focus { border-color: var(--accent); }
#exp-n-input::placeholder { color: var(--muted); }

/* History */
.hist-section {
    border-top: 1px solid var(--border);
    padding-top: 14px;
}

.hist-header {
    font-size: 11px;
    color: var(--muted);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-family: var(--sans);
    margin-bottom: 10px;
}

#liste-historique {
    list-style: none;
    max-height: 160px;
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
}

#liste-historique li {
    font-size: 12px;
    color: var(--muted);
    padding: 6px 0;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    gap: 8px;
}

#liste-historique li span.eq {
    color: var(--accent-dim);
}

#liste-historique li span.date {
    font-size: 10px;
    color: #797980;
    white-space: nowrap;
    align-self: flex-end;
}