:root {
    --bg-dark: #0f1115;
    --bg-panel: #1a1d24;
    --border-color: #2a2e37;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --accent-primary: #3b82f6;
    --accent-hover: #2563eb;
    --anchor-a-color: #ef4444; /* Red */
    --anchor-b-color: #10b981; /* Green */
    --climber-color: #f59e0b;  /* Amber */
    --rope-color: #64748b;
    --vector-color: #f8fafc;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.5;
    overflow: hidden; /* Prevent scrolling if possible */
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh; /* Fallback for older browsers */
    height: 100dvh; /* Dynamic viewport height for mobile Chrome/Safari */
    padding: 1.5rem;
    max-width: 1600px;
    margin: 0 auto;
}

header {
    margin-bottom: 1.5rem;
}

header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(to right, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    color: transparent;
}

header p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

main {
    display: flex;
    flex: 1;
    gap: 1.5rem;
    min-height: 0; /* Important for flex child with canvas */
}

.canvas-container {
    flex: 1;
    background-color: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

canvas {
    display: block;
    width: 100%;
    height: 100%;
    cursor: grab;
    touch-action: none; /* Prevent scrolling on mobile when dragging */
}

canvas:active {
    cursor: grabbing;
}

.control-panel {
    width: 350px;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    overflow-y: auto;
}

.panel-section {
    background-color: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
}

.panel-section h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.setting-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.5rem 0;
}

.setting-row label {
    font-size: 0.95rem;
    color: var(--text-primary);
    font-weight: 500;
}

.input-with-unit {
    display: flex;
    align-items: center;
    background-color: #1e293b;
    border: 2px solid #3b82f6;
    border-radius: 6px;
    box-shadow: 0 0 8px rgba(59, 130, 246, 0.3);
    transition: all 0.2s;
    cursor: text;
}

.input-with-unit:hover {
    border-color: #60a5fa;
    box-shadow: 0 0 12px rgba(96, 165, 250, 0.5);
}

.input-with-unit:focus-within {
    border-color: #93c5fd;
    box-shadow: 0 0 16px rgba(147, 197, 253, 0.6);
}

.input-with-unit input {
    width: 70px;
    background: transparent;
    border: none;
    color: #ffffff;
    font-weight: 700;
    padding: 0.5rem;
    text-align: right;
    font-size: 1rem;
    font-family: inherit;
    -moz-appearance: textfield;
}

.input-with-unit input::-webkit-outer-spin-button,
.input-with-unit input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.input-with-unit input:focus {
    outline: none;
}

.input-with-unit span {
    padding: 0.5rem 0.75rem 0.5rem 0.25rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.file-upload-row {
    margin-top: 0.5rem;
    padding-top: 1rem;
    border-top: 1px dashed var(--border-color);
}

.file-input-hidden {
    display: none;
}

.upload-btn {
    background: linear-gradient(to right, #3b82f6, #2563eb);
    color: #ffffff !important;
    border: none;
    padding: 6px 14px;
    border-radius: 6px;
    font-size: 0.9rem !important;
    font-weight: 700;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(59, 130, 246, 0.4);
    transition: all 0.2s;
}

.upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 14px rgba(59, 130, 246, 0.6);
}

.upload-btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 4px rgba(59, 130, 246, 0.4);
}

.scroll-spacer {
    height: 150px;
    flex-shrink: 0;
}

.loads-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.load-card {
    background-color: var(--bg-dark);
    border-radius: 8px;
    padding: 1rem;
    border-left: 4px solid transparent;
    transition: transform 0.2s;
    flex: 1;
}

.load-card:hover {
    transform: translateX(4px);
}

.load-card.left-anchor { border-left-color: var(--anchor-a-color); }
.load-card.right-anchor { border-left-color: var(--anchor-b-color); }

.card-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.indicator {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.left-anchor .indicator { background-color: var(--anchor-a-color); }
.right-anchor .indicator { background-color: var(--anchor-b-color); }

.card-header h3 {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.load-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

.load-value .unit {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.load-angle {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.decomposed-loads {
    display: flex;
    gap: 1rem;
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
}

.decomp-item {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.decomp-item span {
    color: var(--text-primary);
    font-weight: 600;
}

.info-box {
    background-color: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-radius: 8px;
    padding: 1rem;
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
}

.info-box svg {
    width: 20px;
    height: 20px;
    color: var(--accent-primary);
    flex-shrink: 0;
    margin-top: 2px;
}

.info-box p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.warning-state {
    color: #ef4444 !important;
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

@media (max-width: 768px) {
    body {
        line-height: 1.1;
    }
    .app-container {
        padding: 0;
    }
    header {
        margin-bottom: 0;
        padding: 4px 8px;
    }
    header h1 {
        font-size: 1.1rem;
    }
    main {
        flex-direction: column;
        gap: 0;
    }
    .control-panel {
        width: 100%;
        max-height: 25vh;
        gap: 0;
    }
    .canvas-container {
        min-height: 50vh;
        border-radius: 0;
        border-left: none;
        border-right: none;
        border-top: none;
    }
    .panel-section {
        padding: 8px;
        border-radius: 0;
        border-left: none;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    .panel-section h2 {
        font-size: 1rem;
        margin-bottom: 2px;
        padding-bottom: 2px;
    }
    .setting-row {
        padding: 1px 0;
    }
    .input-with-unit input {
        padding: 2px;
    }
    .input-with-unit span {
        padding: 2px 4px 2px 2px;
    }
    .file-upload-row {
        margin-top: 1px;
        padding-top: 2px;
    }
    .upload-btn {
        padding: 2px 6px;
    }
    .loads-container {
        flex-direction: row;
        gap: 2px;
    }
    .load-card {
        padding: 2px 4px;
        border-radius: 4px;
    }
    .card-header {
        gap: 4px;
        margin-bottom: 1px;
    }
    .indicator {
        width: 8px;
        height: 8px;
    }
    .load-value {
        font-size: 1.1rem;
    }
    .load-angle {
        font-size: 0.75rem;
        margin-top: 1px;
    }
    .decomposed-loads {
        display: none;
    }
    .scroll-spacer {
        height: 60dvh; /* Extremely tall spacer on mobile to allow deep scrolling */
    }
}